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The blood alcohol concentrations (BAC) were estimated by Breathalyzer at various intervals after drinking in 18 drivers, who estimated the time of their last drink; in 16 subjects who drank various alcoholic beverages; and in 11 subjects who drank various alcoholic beverages and then drove a car through an obstacle course. The ranges of Breathalyzer readings for the 3 groups were 0.08-0.20%, 0.06-0.13%, and 0.09-0.20%. Analysis of all the readings and comparison with expected values (calculated by using the known metabolic rate of alcohol) indicated that, when BACs of 0.06 to 0.20% have been reached by the time the test is made, and if the Breathalyzer reading is determined within 2 hr following a driving incident, the BAC is not practically different from what it was at the time of the incident because the rate of change during a 2-hr interval is less than the analytical error of the test procedure. The medicolegal implications are discussed.

During the first 10–11 days of life of the rabbit there was a significant increase in the ‘minimal observed’ O2 consumption measured in a thermoneutral environment. At the appropriate thermoneutral environmental temperature an LD50 period of bilateral hind-limb ischaemia had no effect on the O2 consumption of 1-, 5- to 6-, 10- to 11- and 21- to 25-day-old rabbits until shortly before death. 1 h after a 3 hour-period of bilateral hind-limb ischaemia in a thermoneutral environment the metabolic response of the 1- to 2-day-old rabbits to cold exposure was impaired. In the uninjured 1- to 2-day-old rabbits, the summit metabolic rate was recorded at an ambient temperature of 20°C giving a metabolic quotient of 3.5, whereas in the injured (LD80) 1- to 2-day-old rabbits the summit metabolic rate was recorded at 27°C with a metabolic quotient of 2.1. The results are discussed with special reference to the effects trauma may have on the thermoregulatory role of brown adipose tissue in the newborn rabbit.

The effect of injury on the metabolism of cerebral glycogen was investigated. The glycogen content of the cortex decreased 10 min after injury and increased 24 h after injury. Glucose and glucose-6-P decreased at 1 min and increased at 10 min after injury. The metabolic rate of the injured cortex was diminished to half the control value at 30 sec and 1 min, and was increased at 10 and 60 min following injury. The concentrations of cyclic AMP in the injured cortex increased 7-fold 1 min after injury. The fraction of phosphorylase in the active form (a) was increased relative to controls at 1 and 10 min after injury and subsequently returned to control values. The active form of glycogen synthetase was increased 10 min after injury. The turnover of cerebral glycogen was accelerated immediately after injury, and decreased 24 h later. The increased half-time of glycogen turnover and decreased phosphorylase a activity that the accumulation of glycogen is a result of decreased glycogenolysis.

1. Allometric plots were used to separate Libinia emarginata into three male growth stages; immature, prepubescent, and mature; and two female stages; immature-prepubescent, and mature.2. The existence of two optional prepubescent molts in males allows a 2.75-fold variation in mature (non-molting) length; and one optional molt in females allows a 1.75-fold variation in mature length.3. Because of the very great size range in mature crabs (especially males), there are apparently two reproductive strategies; small mature size and several reproductive years, and large size with one reproductive year.4. The regression of routine oxygen consumption, measured over the entire size range of this crab, exhibits virtually the same slope (0.81) as found by Zeuthen (1953) for crustacea in general.5. The maximum capacity of the stomach, and the maximum hepatopancreas wet weight follow the same allometric relation (slope or a) as the oxygen consumption, in agreement with the idea that metabolic rate is reflected in the...

Brooke, O. G., Cocks, Th. and March, Y. (Tropical Metabolism Research Unit, University of the West Indies, Kingston, Jamaica). Resting metabolic rate in malnourished babies in relation to total body potassium. Acta Paediatr Sand.63: 817, 1974.—Fasting metabolic rate was investigated in 53 malnourished children and 17 controls of similar age. Total body potassium (TBK) was also measured in 18 of the malnourished children and in all the controls, so that metabolic rates could be compared in relation to a measure of metabolically active tissue. In newly admitted malnourished children specific potassium depletion was corrected orally while they were given a maintenance diet. Resting metabolism correlated better with TBK than with weight, height or surface area in control and recovered children, but metabolic rate per unit TBK declined with increasing body-weight (r=-0.51). This negative correlation became insignificant if metabolic rate was expressed in terms of TBK“. In the malnourished children resting metabolic rate was reduced compared with control and recovered values, when expressed in terms of weight, height or surface area. The results were aeonfirmed by a comparison of metabolic rates per unit TBK % which showed a reduction of about 27% in the malnourished children. No significant difference was found between children with marasmus and those with oedematous malnutrition. During rapid growth fasting metabolism was increased. We conclude that oxygen consumption in metabolically active tissues is reduced in all forms of untreated infantile malnutrition.

1. 1. The oxygen consumption of running red squirrels is 1·4–2·8 times greater than that of resting squirrels. 2. 2. Incline running necessitates a higher aerobic metabolic rate than running at the same velocity on the horizontal. Further, the incremental increase in aerobic metabolism with increasing velocity is greater the steeper the incline. 3. 3. When metabolism is plotted as a function of velocity the y-intercept (extrapolated zero running velocity) is greater than resting metabolic values and all regressions intercept the same point regardless of angle of running. 4. 4. A multiple regression analysis of parameters affecting metabolism of running red squirrels yields the following relation: M run = 2·42 + 0·77V+1·67VG , where V = km/hr and G = sine of angle of incline. 5. 5. The following general equation to predict metabolic rate of red squirrels (at rest or active) was generated : M = α[1·50 + 0·085(20- T A )]+0-77V+1·67VG , where a is a coefficient equal to 1·12 if the animal is running or equal to 1·0 if the animal is resting and TA equals air temperature. 6. 6. The data suggest that not only velocity of running but also angle of inclination and ambient temperature may significantly affect metabolic rate of running red squirrels.

A method of prediction of age of menarche from the height and weight of a girl at each age from 9 through 13 years using quartiles of total body water as percent of body weight, an indicator of body composition, particularly fatness, at each age is presented. A similar method to predict age of initiation of the adolescent growth spurt from the height and weight of a girl at age 8 years is also given. Comparison of the results with prediction by other methods supports the idea that the ratio of lean body weight to fat and the metabolic rate per kilogram are important for the determination of sexual maturation. The time difference between actual and predicted age of menarche was six months or less for 59% of the subjects at age 12, 53% at age 11, 48% at age 10, and 47% at age 9.

SUMMARY1. Six experiments each with 2 groups of 9 pigs (9 castrated males and 9 females), 26 to 31 kg initial weight, were kept in a large indirect calorimeter equipped with two identical pig pens. In each pen nine animals were housed for periods of 6 to 8 weeks. The floors tested were: asphalt, straw bedding on asphalt (25 mm straw on asphalt), and concrete slats. Two experiments, each of four periods, were performed on each of the floors. The temperature in the calorimeter was changed in stepwise fashion by 2 to 3°C at intervals of 2 to 3 days. In periods 1 and 3 the temperature was decreased stepwise from 20·23°C to 5·8°C, and in periods 2 and 4 in the reverse order. Gaseous exchange was measured at each of the temperatures for 48 hr. Feeding level was kept constant at about 1160 kJ meta-bolizable energy/kg0·75.day.2. Heat production and energy balance per unit of feed intake were similar on all floors in the zone of thermoneutrality and the derived maintenance requirements were also similar with a mean value 438 kJ/kg0·75.3. The effective critical temperature of animals weighing 40 kg was 11*5 to 13°C on straw bedding, 14 to 15°C on asphalt and 19 to 20°C on concrete slats.4. At temperatures below the critical temperature heat production was increased. The increase in extra thermoregulatory heat production was on average 8·9 kJ/kg0·75 per °C below the effective critical temperature. Between the various floor types differences in this increase were noticed, but were not significant.5. Body-weight gains on asphalt and straw bedding were similar; on concrete slats the body-weight gain was significantly reduced.

Measurements of ingested ration, assimilated ration and metabolic rate in Mytilus edulis L. of different sizes have been integrated to provide an estimate of energy balance, which in turn describes the physiological state of the animal. These data allow the empirical determination of growth efficiency and ration. Growth efficiency increases hyperbolically with increasing ingested ration to reach a maximum, after which efficiency decreases as ration is further increased. The optimum ration for efficient growth increases with increasing weight of the mussel; maximum growth efficiency decreases with increasing body weight.

Based on data for 53 mammalian species reported in the literature, statistical analyses revealed that daily sleep quotas correlate positively with metabolic rate and negatively with maximum life span

The results (Table 2) showed that sodium phenobarbitone pretreatment did not affect the metabolic rate in vivo of dimethylnitrosamine and the LDSo was unchanged. On the other hand, 20-methylcholanthrene treatment not only enhanced the metabolic rate of dimethylnitrosamine in uivo to 125% of the control, but also significantly increased the toxicity of dimethylnitrosamine in the young male rats. The results of our studies show that phenobarbitone and 20-methylcholanthrene induced hepatic dimethylnitrosamine demethylase activity in young and mature rats of both sexes. These findings are in agreement with thereported induction of dimethylnitrosamine demethylase activity in mice after the administration of polychlorinated biphenyls, compounds known to induce drug-metabolizing enzyme activity (Czygan et al., 1973). However, this inductive effect in vitro was not reflected in the metabolic rate of dimethylnitrosamine in the intact animal. Further, the toxicity of dimethylnitrosamine appeared to be influenced by the metabolism in uivo. Our findings question the relevance of hepatic dimethylnitrosamine demethylase activity as an index of the metabolism in uivo and the consequent toxicity of dimethylnitrosamine in the rat.

Based on data for 53 mammalian species reported in the literature, statistical analyses revealed that daily sleep quotas correlate positively with metabolic rate and negatively with maximum life span

The oxygen consumption of five larval stages of the Calliphoridae Callitroga macellaria, Lucilia cuprina , and Calliphora vicina was analysed at different temperatures. There are differences in temperature adaptation in these three species as well as in the feeding and non-feeding larvae of Callitroga . Within fixed limits of tolerance the reaction to changes in temperature is more intensive in feeding than in non-feeding larvae. A high metabolic rate is related to high levels of sensitivity to temperature changes. At particular temperatures oxygen consumption generally decreases with age. The results partly confirm the well-established fact that at the same temperature the metabolic rate of ‘cold’-adapted stages and species is relatively high as compared to ‘warm’-adapted ones. During the course of experiments oxygen consumption was frequently inconstant as can be seen by comparing the oxygen consumption of the first and second parts of the experiments, or more exactly, by regression analysis of the oxygen consumption rates throughout these experiments. Increasing and decreasing oxygen consumption depends on temperature adaptation which indicates regulatory processes. A method to determine standard temperature using measurements of respiratory metabolism is discussed.

Starting with the Krogh-Erlang equation, and the assumptions necessary for that simple model, an equation for mean tissue oxygen pressure is derived and solved for a number of plausible conditions in order to examine the degree to which venous blood P O 2 approximates the calculated mean tissue value. For normal resting conditions there is a remarkably close agreement between the two values, but there are significant deviations when capillary density, metabolic rate, hemoglobin concentration and cardiac output are altered. The purpose of the analysis is not to defend quantitatively the Krogh tissue model, which is admittedly crude, nor to propose that the mean tissue P O 2 has any unique physiological significance, but to make a first approximation of tissue oxygenation, and to define the usefulness of venous blood as an index of mean tissue P O 2 applicable to the Krogh model. Insights are provided concerning optimal modes of response to hypoxic stress and the. problems of tissue oxygenation in physiological and patho-physiological states.

Schiller, G. and Karschon, R., 1974. Microclimate and recreational value of tree plantings in deserts. Landscape Plann., 1: 329–337. Microclimatic measurements were made in a floodwater irrigated plot (“liman”) of Eucalyptus camaldulensis Dehn, of about 0.3 ha, and in the open desert. While air temperature and vapour pressure did not differ appreciably in the two areas, black-body temperature, global radiation, evaporation and wind speed were conspicuously lower in the liman than in the open. As a result, the Index of Thermal Stress (I.T.S.) and the Thermal Sensation (T.S.) of man, computed for two levels of metabolic rate, were always lower under the tree canopy than in the open. During the summer, lower values of I.T.S. and T.S. in the liman provide for greater thermal comfort, thereby enabling tree plantings in deserts to satisfy the recreational needs of the public during the main season of outdoor recreation. During the winter, the liman is clearly too cold and visitors may be expected to stay outside the grove. The implications of the findings for recreation management are discussed and the absence of an “oasis effect” in liman plantations is emphasized.

Chicks and rats were compared in their response to dietary thyroprotein and liver supplements. The addition of high levels of thyroprotein to casein-glucose diets reduced weight gain and decreased survival time of growing chicks and albino rats. Concomitant supplementation with liver partially prevented growth depression and increased survival time. Heart and kidney weights of chicks were increased by thyroprotein and decreased by liver supplements. Liver weights appeared to be similarly, but less dramatically, affected. Spleen weights were generally reduced by thyroprotein and increased by liver while effects of thyroprotein on thymus weights were variable and inconclusive. In chicks fed thyroprotein supplements, oxygen consumption rates decreased rapidly after the initiation of fasting and were equal or slightly below euthyroid controls after 24 hours. In non-fasted chicks and rats, oxygen consumption was increased by thyroprotein and the addition of liver to thyroprotein supplemented diets partially prevented the increase in oxygen consumption. However, liver supplementation did not affect the endogenous metabolic rate of chicks. It appears that similar mechanisms are involved in the antithyrotoxic response of the two species.

Propulsive wavelength, tail-beat frequency, trailing-edge amplitude, critical swimming speed and oxygen consumption rates have been measured for sockeye salmon in which the trailing edge depth and caudal-fin area were variously reduced by partial caudal-fin amputation. The swimming mode was sub-carangiform. The 45 min critical swimming speed for intact fish was 61·6 cm/sec (3·0 l/sec). The critical speed was not significantly reduced by removal of either the epaxial or hypaxial caudal-fin lobes, but was reduced significantly (P < 0·05) to 51·8 cm/sec (2·5 l/sec) when both lobes were removed. The mean length of the propulsive wave was 1·00 body length, and was not affected by the caudal-fin surgery. Both tail-beat frequency and amplitude increased with speed, their product linearly so. Normalization of data in relation to the physiological maximum at the critical swimming speed showed no relative changes in frequency and amplitude. No significant differences were observed in standard or active metabolic rates. General equations describing thrust (Lighthill, 1969) and drag were compared. It was shown that the drag on the caudal fin was markedly increased by lateral propulsive movements as suggested by Bone ‘s boundary-layer thinning hypothesis (Lighthill, 1971). Drag coefficients for the caudal fin were one to two orders of magnitude higher than would be expected in the absence of lateral movements. It is considered that the principal function of the caudal fin is in manoeuvre and acceleration.

Studies on respiration and metabolic rate in relation to body size have been carried out for an important fouling molluscCongeria sallei, Recluz. The oxygen consumption varied from 0·038 ml/hr to 0·804 ml/hr depending on the body size. The metabolic rate varied inC. sallei from 6·012 to 0·805 ml/gm/hr, the highest rate being obtained in the smallest animal. The respiration by the animals was found to be proportional to the power of 0·5845 of the body weight and the relation of surface area to metabolism has been thus indicated.

Plantings of Rideau and Cappelle Desprez winter wheat (Triticum aestivum L.) were made on 12, 21, and 28 September 1972, and sampled for cold hardiness and survival throughout the fall, winter, and spring. Samplings in winter from frozen soil were made with the aid of a concrete chipper with a vertically oscillating blade. Both wheat cultivars hardened rapidly in fall but the decline in hardiness and vigor under ice during winter was more rapid in Cappelle Desprez plants. Rideau plants rehardened after thawing of the ice cover. The greater hardiness and survival of Rideau plants was due possibly to their lower metabolic rate and consequent energy conservation under ice cover.

Direct separate and simultaneous determinations of pulmonary and cutaneous V O 2 and V CO 2 were made on the large aquatic salamander Amphiuma means means acclimated to 5, 15 and 25 °C. Differences in temperature significantly affected metabolic rate- and the relative partitioning of gas exchange. The animals were predominantly water breathers at 5 °C (92% of total V O 2 and 100% of total V CO 2 At 25 °C, the lungs assumed a greater role and accounted for 56% of the total V O 2 and 23% of the total V CO 2 Eleven Amphiuma submerged at 25 °C in air saturated water perished within 2 days; this aquatic animal, therefore, is an obligate air breather at higher metabolic rates. The lungs of Amphiuma are long, profusely vascularized and highly septated. Cineradiographic studies show that the lungs are efficiently ventilated when the animal surfaces for air. The pulmonary capacity of Amphiuma is similar to that of Siren lacertina and is of substantial adaptive value to both species which frequently find themselves in adverse aquatic environments ( e.g . warm, shallow and stagnant bodies of water which are often both hypoxic and hypercarbic).

The metabolic turnover rate and the transcapillary escape rate of albumin were studied using 131 I-labeled human albumin in nine untreated subjects suffering from essential hypertension. The average mean arterial blood pressure of these subjects was 162/109 mm Hg; seven subjects had grade I-II funduscopic changes. Plasma albumin concentration was normal, but plasma volume was reduced ( P < 0.05) in these subjects. Thus, the previously reported moderate decrease in the intravascular albumin mass of hypertensive subjects was confirmed; the average value for intravascular albumin mass in the present study was 62.8 g/m2 surface area compared with a normal value of 70.6 g/m 2 (-11%, P < 0.05). A surprising finding was a marked enhancement of albumin metabolic rate in essential hypertension. The fraction of intravascular albumin mass metabolized per 24-hour period was on the average 14.4% compared with a normal value of 8.4% (+72%, P < 0.001). The rate of synthesis was 9.1 g/24 hours m -2 compared with a normal value of 5.9 g/24 hours m -2 (+54%, P < 0.001). Total body albumin mass was decreased proportionally to intravascular albumin mass. Confirming a previous observation, we found an increase in the transcapillary escape rate of albumin (fraction of intravascular mass passing to the extravascular space per unit time) from a normal average of 5.6%/hour to 7.5%/hour (+34%, P < 0.001). There was a statistically significant positive correlation between the transcapillary escape rate of albumin and blood pressure ( P < 0.05). These findings can best be explained by increased filtration due to the high arterial blood pressure. There was also a positive correlation between the transcapillary escape rate and the fractional catabolic rate of albumin ( P < 0.05). This finding supports the concept that albumin is catabolized in connection with its permeation through the capillary endothelium.

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters. hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation Submitted on July 6, 1964

Synopsis 1. Resting metabolic rate (RMR) and fasting metabolic rate (FMR) were periodically determined, using an open air circuit master system, from January to September in 10 White Leghorn, 10 Plymouth Rock and 20 New Hampshire × White Leghorn mature laying birds fed ad libitum. 2. The relationship of metabolic rate (l.O2/hr.) to body weight (kg.) in the pooled data followed the 0.795 W0.61 equation for the fasting level, and 0.916 W0.59 for the resting level. The expression of metabolic rates as litres oxygen per kg. body weight can lead to serious errors if birds of differing body weights are compared. 3. Heat increments of feeding (estimated by RMR‐FMR) gradually increased with rising environmental temperature, with only slight initial change in the FMR, followed by marked reductions in both the FMR and the RMR at the higher temperatures. It is suggested that a decrease in the FMR may allow for a reduction in the RMR in the hotter season, without this necessarily being linked with a depression in the...

SummaryFurther evidence is submitted that a terrestrial mammal, the hamster, has a deep-seated lunar rhythmic component which appears to be derived directly in response to subtle, pervasive geophysical variations. This is reflected in the degree of spontaneous activity and hence would obviously be importantly reflected in standard metabolic rate. The mean monthly range for the motor activity is more than 15%. This suggests that a sol-lunar rhythmic complex such as is now well-established for marine intertidal species occurs also in non-marine forms. It also suggests strongly that fluctuations in hitherto largely disregarded pervasive, weak geophysical variations have substantial influences upon mammals.

1. 1. A simple method for controlling water vapor pressures (WVPs) in an open-flow system is described. 2. 2. High WVPs (30 mm Hg) alter the normla homeothermic response to ambient temperature variation in laboratory mice such that metabolic rate becomes independent of ambient temperature, particularly at ambient temperatures above the thermoneutral zone. 3. 3. WVPs of 10 and 20 mm Hg do not affect the normal, metabolism-ambient temperature relationship.

SummaryAlthough alligators are quite active in the winter if the temperature is high they have a pronounced hypoglycemia and no appetite. There is no seasonal change in metabolic rate in either the alligator or caiman. The caiman does not hibernate. Pituitary powder produces prolonged hyperglycemia and increases the metabolic rate. Desiccated thyroid powder has no effect on blood sugar. Neither glucose nor insulin had any effect on metabolic rate.

1. 1. After cold exposure, elevation in oxygen consumption was seen in newly hatched young. 2. 2. Monoamines and thyroxine had no metabolic stimulating effect. Corticosterone stimulated metabolic rate already 16–20 min after injection. 3. 3. Cold exposure elevated slightly corticosterone and noradrenaline contents in the blood plasma, but adrenaline content decreased significantly.

Dietary antithyrotoxic substances such as liver residue and hemoglobin (Hb) partially inhibited the absorption and enterohepatic recycling of oral or ip injected thyroxine (T4). Approximately twice as much thyroxine was excreted into the feces and only half as much T4 was absorbed into the plasma when a single dose of 131I-T4 was given to rats receiving a diet containing one of the antithyrotoxic substances. The poor T4 absorption was probably the result of at least 2 contributory factors. First, antithyrotoxic substances caused an oral dose of T4 to move rapidly through the lower ileum and large intestine, which are the most active sites for T4 absorption. The fecal mass was much greater in these animals, and this may have been responsible for the greater intestinal motility. Second, T4 probably formed an unavailable complex with the antithyrotoxic substance or its degradation product. Two types of evidence were obtained to support this concept: 1) the fecal T4 from Hb-fed animals had little biological a...

SummaryFasting baby chicks from 5 to 20 days of age showed an increase in metabolic rate with increasing age. This increase was 0.2 to 1%† per day for the metabolic rate per unit body weight, 2% per day for the metabolic rate per kg3/4 and 3% for the metabolic rate per unit surface area. Baby chicks thus deviate systematically from the rule which is valid for the relation of body size and metabolism in mature homeotherms. This confirms an earlier deduction based on an observation on full fed baby chicks.

1. 1. The small Inca doves (weight 42 g) of the southern Arizona deserts live an urban existence where water in continually available but where temperature fluctuations are extreme. 2. 2. Nocturnal body temperatures are significantly lower than in daytime, but pulmocutaneous water loss rates are reduce at night primarily by metabolic reductions and extreme quiescence. 3. 3. The standard daytime metabolic rate is 1·11 cm3 O2/g/hr in thermal neutrality at TA=35°C; this is 21 per cent below that predicted from the King-Farner equation for non-passerine birds, thereby effectively reducing metabolic heat production. 4. 4. Under conditions of high TA(>35°C) hyperthermia is pronouced. But gular flutter commences at TA=42°C, increasing evaporative cooling and decreasing the TB−TA gradient. At TA=44°C metabolic heat is dissipated as fast as it is produced and equality of TB and TA is maintained.

Summary The oxygen consumption of 27 normal babies was measured at an environmental temperature of about 35°C, approaching this temperature either from 30°C or 40°C. There was a decrease in oxygen consumption at an ambient temperature of 40°C compared with 35°C, provided the baby remained asleep and motionless. The oxygen consumption at an environmental temperature of 35°C when this had been reached by coming from 40°C was 15% higher than when it had been reached by warming from 30°C. This difference could not be explained by differences in skin-air temperature gradients nor by a Q 10 effect.

The essential feature of a stream is the continuous flow of water, and the various schemes of classification of streams and the associated fish fauna are largely based on factors which determine the average velocity. These schemes have been better developed in Europe than elsewhere, probably due to the relative uniformity of the climate. The characteristic features of fish inhabiting the more rapid streams can be related to the constraints imposed by this environment, and particularly by the need for the population to maintain its position against the continuous tendency of the stream to transport it downstream. Physiological factors associated with the normally high oxygen level and the need for continuous activity include a high routine metabolic rate, a high oxygen threshold for full activity, and, possibly, a high lower lethal limit for dissolved oxygen. Adult fish maintain their position either by continuous swimming in midwater, and these usually have a streamlined shape which is circular or laterally compressed in cross-section, or by avoiding the current and living closely attached to or in the substrate and these are usually dorso-ventrally depressed. The eggs are usually protected from the current by burying them in the substrate, sometimes in a well-developed nest. The general absence of vegetation in rapid streams results in the fish generally feeding principally on the available animal food, usually small invertebrates taken either in the drift or off the bottom. The solitary territorial behaviour which characterizes most stream-living fish probably leads to more even distribution and more efficient utilization of the food supply.

1. Fifteen apparently healthy persons were exposed to air enriched with positive or negative ions at 78° F. and 87° F. Average ion counts at 78° F. were 12,324 positive ions per ml. and 5,451 negative ions per ml. The averages at 87° F. were 14,865 positive ions per ml. and 5,442 negative ions per ml. Relative humidity was kept at 50% and air motion was 28 ft./min.2. Seven sensations related to comfort (thermal sensation, humidity sensation, sensible perspiration, air motion, pleasantness, mood and fatigue) were recorded, pulse rate and oral temperature were measured.3. In the experiments at 78° F. mood was improved (P < 0·001) by positive ionization. All other qualities remained unaffected by positive ionization. No effect was found under negative ionization at the ion concentration applied.4. In the experiments at 87° F. five sensations (thermal sensation, sensible perspiration, pleasantness, mood and fatigue) were significantly (P < 0·001) improved by ionized air. In general, as can be seen from the significantly differences between grand means, the subjects felt cooler, perspired less, felt more pleasant, were in a better mood, and felt less fatigued under the influence of air enriched with ions.Air motion sensation, humidity sensation, pulse rate and oral temperature were not affected by ionization.5. As different individuals may vary in their response to ionization, individual preferences were tested. These tests indicated that at 87° F. six out of the fifteen persons tested preferred ionized air (P < 0·001). One person preferred air not enriched with ions (P = 0·0091).

I DISCUSSED the relation between the physiological dominance and the biological effects of rays before the American Roentgen Ray Society in Swampscott, Massachusetts, on September 3, 1924. The time allowed for my paper at the Swampscott meeting permitted me to go into the subject in more detail than I will be able to do at this time. The discussion in Swampscott will be printed in the American Journal of Roentgenology and Radium Therapy. Both of these discussions are based upon the results of some experiments which were formally presented to the American Association for Cancer Research at Buffalo, New York, in the Spring of 1924. The relation between physiological dominance and susceptibility to radiation is of peculiar interest to the clinician because of its bearing on the rationale of the treatment of cancer by radiotherapy. Physiological dominance is correlated with metabolic rate and it is a quite generally accepted biological fact that a high metabolic rate and susceptibility are also correlated. Th...

1. Acclimation to constant cold also causes in mice a decrease in the intensity of muscle shivering in cold and an increase in the metabolic rate of the animal and in the succinic dehydrogenase complex activity in the liver and skeletal muscles. 2. The succinic dehydrogenase complex activity in the liver depends on the acclimation temperature at least over a range from 5° to 32° C. 3. Acclimation of mice to short-term exposures to cold does not affect metabolic rate of the animals or the succinic dehydrogenase complex activity in the liver but causes an increase in the metabolic response to injected l-noradrenaline. 4. The induced tolerance to the hypothermisant effect of promazine in mice develops slower in a thermoneutral environment than at room temperature.

It has long been known that gradual acclimatization may enable an animal to withstand temperatures so high that they would speedily prove fatal were the change made abruptly. There is some evidence, though of less extent, relating to extreme reductions of temperature. It is a curious fact that tolerance to high temperatures, once acquired, may persist for considerable periods after the return of the organism to the temperature from which it was taken, or even to a considerably lower one. Some rather lasting, though probably not permanent, change has been brought about in the physical or chemical properties of the organism. Regarding the nature of this change, various hypotheses have been offered. Certain authors have suggested the probability of a rise in the coagulation point of proteins, due to a loss of water in the tissues, as a result of exposure to higher temperatures.' Others have pointed to the r6le played by differences of metabolic rate in determining the resistance of organisms not only to heat but to other lethal agents. Experiments by Child (1913 and later) "demonstrate the existence of a relation between the length of life (physiological resistance) of the animals or pieces in KCN, alcohol, and various other anesthetics and the rate of the metabolic reactions or certain of them, probably the oxidations." Miss Behre (1918), working in Child's laboratory, found for a planarian that transfer to a higher temperature increased the metabolic rate and, conversely, that transfer to a lower temperature decreased this. Much more important, for present purposes, was the fact that any such transfer was followed by a regulative process, so that a worm which had been kept for a certain length of time at a given temperature displayed a definitely higher rate of metabolism than one which was transferred to this directly from a higher temperature, and a definitely lower rate than one which was transferred directly from a lower temperature. The indices of metabolic rate employed by her were susceptibility to poisoning by KCN, and the production of CO2.

Summary. A control study was made concerning the existence of Mansfeld's thermothyrin A. Serum taken from human subjects and rabbits after thermal stress was injected into mice and their metabolic rate was measured using a direct calorimetric method. No significant changes in the metabolism were observed.

An attempt was made to determine in the developing fowl embryo whether injections of thyroxin into the incubating egg would lead to a modification of the processes of sexual differentiation. The injections into the air space were made during the 3rd day of incubation, that is, at a time before the differentiation of the gonads in the two sexes can be demonstrated. Of the 190 eggs injected with thyroxin, 39 embryos survived of which 12 were markedly affected, reduced size of embryos being regarded as an indication of a marked hyperthyroidism which has resulted in an increase in the metabolic rate. No effect on the processes of sexual differentiation in either sex was found. The effect of the injections was not apparent before the 1 ith day. It will be attempted in a further series of experiments to determine whether this is a specific reaction of the thyroxin or whether it is due to mechanical hindrances to the absorption of the thyroxin into the foetal circulation until a considerable time after the injection. These experiments can not at present lead to any definite conclusion as to the relation between increased metabolism and the processes of sexual differentiation.

1. The half-lives of homologous gamma globulins labelled with I131 agree well with the half-lives of passively administered homologous antibodies and provide a simple, quantitative tool for the determination of antibody half-life when immunochemical techniques are difficult to apply. 2. The half-lives of gamma globulin or antibody vary markedly from species to species and apparently even among age groups within a species. 3. The half-lives of gamma globulin or antibody seem to be dependent, at least in part, on the metabolic rate of the host.

The population dynamics and energetics of two populations of Diaptomus gracilis have been studied in two Thames Valley reservoirs. The seasonal changes in the standing crop biomass varied from a low of 0.3 Cal/m2 to a high of 7 Cal/m2. Although the population overwintered primarily as adults, reproduction was continuous throughout the year. From the mortality rate the production has been estimated to be 52 and 48 Cal/m2 for the Queen Elizabeth II and King George VI reservoirs, respectively. Feeding and respiratory rates of D. gracilis were measured both in the laboratory and in the field simultaneously with the population dynamics in the reservoir. The feeding rate and the rate of assimilation varied with the species of phytoplankton used as food. Filtering rates varied from 0.1 ml copepod—1 day—1 on bacteria to a high of 2.54 on Diplosphaeria, the latter also having an assimilation efficiency of 78% by D. gracilis. Respiratory rates varied with the season. When the metabolic rate was plotted against body...

1. Injection of 10 mg. followed by 15 mg. of 1·2 : 5·6 dibenzanthracene in adult rats did not alter the metabolic rate or the food consumption. 2. These injections, however, produced a prolonged loss of weight and death in 4 out of 8 rats. The deaths occurred 42 to 65 days after injection. 3. The inhibition of the growth of young rats by 1·2 : 5·6 dibenzanthracene was not affected by treating the rats with thyroid or insulin. 4. 1·2 : 5·6 dibenzanthracene in large doses did not affect normal cestrus in rats. This work was made possible by a grant from the Medical Research Council for the maintenance of animals and laboratory expenses, and by a personal grant from the Cancer Control Organisation for South-East Scotland. Thanks are also due to Dr. C. M. Scott for advice and assistance.

On the basis of simple physical considerations the blood flow in a branching circulatory system is studied. The case of two groups of parallel vessels is treated. The vessels of the same group are supposed to be identical. The resistance of each group is determined by the resistance of each vessel in the group and by the number of vessels in the group. From the dependence of the resistance of each vessel on its radius an expression is obtained for the blood flow through each group of vessels in terms of the numbers and sizes of the vessels in each group. The number of open vessels in an organ and the radius of each of those vessels are assumed to depend on the metabolic rate of that organ. The relations so obtained, together with the expression above, are applied to derive the blood flow through an organ as a function of the metabolic rate of that organ. It is indicated that the relations obtained might describe the shifting of blood from one organ to another if the activity of one of them changes. A way is pointed out to treat neural regulation of this phenomenon.