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The sections in this article are: 1 Physics of Acceleration 1.1 Interaction of Forces and Mass 1.2 Acceleration of Circular Motion (Physics of the Centrifuge) 1.3 Acceleration without Inducing Weight 1.4 Acceleration of Aircraft 1.5 Acceleration of Rockets 2 Research Centrifuges 2.1 Sustained-G Centrifuges 2.2 Chronic-G Centrifuges 3 Acceleration Nomenclature 4 Sustained G 4.1 High Sustained G (HSG) 4.2 Cardiovascular Accommodation to +Gz 4.3 Neurologic Accommodation to +Gz 4.4 Lung and Respiration Accommodation to +Gz 4.5 Physiological Accommodation to -Gz ±Gx and +Gy 4.6 G Tolerances 4.7 Adaptation to Sustained G 4.8 Cross Adaptation 4.9 Natural Bases for Sustained-G Homeostasis 5 Chronic G 5.1 Adaptation Process 5.2 Structural and Functional Changes 5.3 Adaptation to Hypo- and Hypergravity Fields 5.4 Utilization of Gravitational G in Space 6 Conclusion

Data are given on the effects of administering small amounts of fumaric acid to rats, guinea pigs, and human subjects daily for prolonged periods of time and to rats in larger doses for short periods. The results of the study described indicate a low degree of toxicity for fumaric acid and sodium fumarate. The possibility of using fumaric acid in place of tartaric acid in foods and drugs is suggested.

SummaryThe laxative action of sodium, magnesium, and calcium fumarates has been compared with that of sodium potassium tartrate in 143 chronically constipated patients. The fumarates have been found as satisfactory as Rochelle Salts as a laxative agent.

This paper extends the argument that cattle ranching and ranchers can be better understood by viewing the ranch resource as generating both production and consumption outputs. It was found that nonmonetary outputs of ranch ownership are the most significant factors in explaining high sale prices of Arizona ranches. Land fundamentalism, rural fundamentalism, and conspicuous consumption/speculative attitudes are the most important of these consumption outputs. The analysis suggests that small town viability and growth in the arid Southwest, and possibly in the West as a whole, may be more likely to occur if rural development policies are not predicated on the economic impact of surrounding ranches.

In the course of some studies on house flies, it became desirable to determine the respiratory exchange of individuals. Since the metabolism of such insects is low, a fairly sensitive apparatus was required. Existing micro-respirometers were not well adapted for use with whole active insects, consequently the apparatus described herein was constructed.

EGGS from individual hens have been shown to be quite uniform with regard to many chemical and structural constituents: The nitrogen, fat and phosphorus content of the yolk (Malcolm, 1901–1902); egg size, shape, and color (Benjamin, 1920); the rate of water evaporation (Dunn, 1923); shell strength (Romanoff, 1929); proportion of thick albumen (Lorenz, Taylor and Almquist, 1934); dry matter (solids) content of albumen (Almquist and Lorenz, 1933); and rate of growth of yolk (Lorenz, 1943). Recent studies on other species such as man and rat (Williams and others, 1951) and the dairy cow (Hancock, 1950) indicate that the intensity of many, if not all, metabolic processes are inherent and collectively form a pattern which is characteristic of the animal. The nature of the environment is known to affect the composition of the egg, and is even more influential than heredity on variation in egg production (Gutteridge and O’Neil, 1942)… .

INTRODUCTION CALCULATIONS of surface area of irregularly or asymmetrically shaped objects may involve complex measuring methods or mathematical computations. In those structures exhibiting symmetry, the procedure may be less complicated; for example, the total surface of a parallelepiped is equal to the summation of the areas of its sides. On the other hand, the surface area of objects has been reckoned using adhesive tape, weights of peelings, or by considering the surface as a function of the two-thirds power of the weight (Mueller and Scott, 1940). The surface area of avian eggs has been estimated in similar ways (Dunn and Schneider, 1923; Murray, 1925; Marshall and Cruickshank, 1938; and Romanoff and Romanoff, 1949), but the most useful and accurate methods have been based on the volume (Romanoff and Romanoff, 1949). However, if the object forms a surface of revolution, like an egg shell, it is possible to perform these measurements utilizing . . .

The effects of the ingestion of diets containing different concentrations of protein on the remaining kidney in adult white rats after a unilateral nephrectomy has been studied. In the animals on the high protein diet (85 per cent casein), actual glomerular and tubular lesions were observed in the kidneys of animals maintained for 90, 120 and 150 days after nephrectomy. In the animals on the standard ration, 18 per cent casein, no significant renal lesions were observed within the experimental period. Spontaneous focal lesions in the kidneys of rats maintained on Sherman's diets "A" and "B" were inconspicuous at the age of 350 days but became progressively more frequent and were commonly observed after 500 days. The animals on the high protein and standard rations were all under 350 days old at the completion of the experiment. It is suggested that the age factor is of importance in that young animals may have greater powers of adaptation in withstanding the injurious effect of high protein rations. The animals on the high protein ration excreted definitely larger quantities of protein in the urine, and showed a higher incidence of casts in periods roughly corresponding to those in which anatomic lesions were observed than did the rats on the standard diet.

(Received for publication, March 16, 1960) The “citric acid cycle” is now regarded as the final common pathway of metabolism serving as the primary route for the oxi- dation of metabolites. Likewise, the thyroid hormone is con- sidered a major regulatory substance for biological oxidations. It, therefore, seemed logical to study possible quantitative altera- tions in the cycle acids in experimental hypo- and hyperthyroid states. The concentrations of the cycle acids in metabolically active tissues, liver and muscle, were determined in experimental hypo- and hyperthyroid and control rats.

IONIZING radiations have long been known to affect biological systems, and a great many radiation effects have been described (Duggar, 1936; Hollaender, 1954). Biological processes are generally inhibited by ionizing radiations, except at low levels, and the biological response to the irradiations is proportional to the dose (i.e., the quantity of radiant energy absorbed by the tissue or organism). Although the mechanism of action of ionizing radiations is not completely understood, they can be used to great advantage in the study of biological processes. Functional alteration of tissues, resulting from irradiation, may be used to interpret the normal process of the tissue. In a study of the physiological processes that lead to the formation of the egg shell and albumen, the surgically exposed oviduct was irradiated with graded doses of X-rays, and the nature of the post-irradiation eggs determined. This procedure resulted in some changes of egg production rate and …

Erythrocyte sedimentation was observed in chicken blood with the aid of a microscope. It was determined that the velocity of an ellipsoid shaped cell (chicken erythrocyte) sedimenting in a dilute suspension of cells can be predicted by Stokes' equation; i.e. it obeys Stokes' Law using the calculated ‘effective radius’ which is defined. Sedimentation of cells in suspensions having greater than 0·003 per cent packed cell volume was characterized by reversing currents resulting from an interaction between the erythrocytes and the liquid medium. Eliminating these currents did not affect the overall erythrocyte sedimentation rate, however.

Summary A technique of venous catheterization has been adapted to dairy cows, which allows numerous blood samples to be taken at short intervals and the frequent, accurate intravenous injection of substances (particularly radioactive material) over a long period with a minimum of disturbance to the animals.

IN BIRDS, a cycle of development and involution of the reproductive organs generally accompanies the mating season. These changes are associated with a renewal of the plumage (i.e., a molt), but the causal relationships between these processes are not certain (Greenwood, 1936). These natural changes in the reproductive organs have been largely eliminated in the domestic chicken, with eggs being produced more or less regularly throughout the year. The hen, however, retains the capacity for involution and regeneration of its reproductive organs, and this sequence may be induced in a number of ways: by withholding feed and water or by excluding light (Hall, 1946), by thyroid administration (Van der Meulen, 1939), by progesterone administration (Adams, 1955; Shaffner, 1955), or by Enheptin feeding (Pino, 1955). The rate of development of the fowl’s reproductive organs with the onset of sexual maturity has been described (Hafez and Kamar, 1955). The size of the …

SummaryOrgan and body mass changes in restrained adult, male domestic fowl were compared with tissue from control and fasted animals. Body mass loss rate in the restrained animals was 63.5% (p < .001) greater than in the fasted group, yet the two groups recovered at the same rate. Compared with controls and fasted animals, restrained fowl exhibited an increase in size of heart, lungs, kidneys, liver, and adrenals but a greater loss of spleen, superficial pectoral muscle, small intestine, and pancreas masses. Relative water content of organs generally increased in restrained and decreased in fasted animals. The data suggest that restraint—although accompanied by inanition—affects organ and body mass in the domestic fowl in a different way than does fasting.

The composition of the oviduct magnum (albumen-forming segment) was determined before and after albumen deposition, and in nonovulating hens. The quantity and composition of material accumulated in the magnum after albumen deposition, but with and without subsequent ovulation, indicate that albumen precursors are formed in at least two steps. A large part, perhaps 45%, of the albumen deposited by the magnum appears to be synthesized and transferred at the time of deposition.