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A mutation in the Cornell K-strain of White Leghorns, first recognized when two adult males in a pedigreed family were definitely smaller than their two other brothers, proved to be an autosomal recessive mutation and gave rise to the autosomal dwarf stock. The effect of this gene (adw) can be recognized during embryonic development and leads to a normal adult, except for a 30% reduction in body weight. Selection for small size, egg production, and egg weight over a period of 15 yr yielded an efficient layer. Production for 11 mo from first egg was at a rate of 70%, with egg weight at 56 g and body weight at 1,160 g at 10 to 11 mo of age, based on data for the last four generations. Viability of the caged hens averaged over 95% for the 13 generations involved. Sexual maturity was delayed by about 2 wk, and good incubation (85+%) required 18+/- more hours than normal. When an autosomal dwarf male is used as a sire and mated to sex-linked dwarf (dw) females, all progeny are of normal size. Compared with problems of mating normal size males with dwarf females, the use of the two types of dwarfism can yield good fertility.

We present the first results from the upgraded version of the scanning photoemission spectromicroscope MAXIMUM, bared on synchrotron undulator fight and on a multilayer-coated Schwarzschild objective. The upgrade involved nearly all parts of the instrument, notably the beamline and the electron analysis system. Micro-images of Fresnel zone plates and of metal test patterns on semiconductor substrates reached a new record in lateral resolution, well beyond 0.1 micron. The first spectromicroscopy tests were also successfully performed on the new instrument, with analysis of f and d core levels in different systems.

Neuron networks have been imaged with the scanning photoelectron microscope MAXIMUM, showing details in the submicron range such as axons, dendrites and their synapses. These results, obtained with the scanning photoemission microscope MAXIMUM, demonstrate that photoemission can reach the lateral resolution required for the life sciences, and prepare the way to the future use in the life sciences of techniques such as ESCA.

We present the first results of high‐spatial resolution x‐ray imaging studies with an upgraded version of the scanning photoemission multiple application x‐ray imaging undulator microscope. The microscope is a multilayer coated Schwarzschild objective that focuses undulator radiation onto the sample. The recent upgrade improved the spatial resolution by a factor six reaching a full width at half maximum value of 0.5 μm. Highly polished mirrors reduced the diffuse background by almost two orders of magnitude and drastically improved the contrast. The improved microscope was used to perform a series of tests on microgrids and reverse Fresnel zone plates. The microscope capability to detect chemical and topological contrast was verified by using patterned metal overlayers on Si and GaAs substrates. Further improvements to increase the flux and the spatial resolution are underway; this includes the installation of a new undulator beamline.

We describe here a unique lithography beamline that delivers x-rays using a flexible arrangement of two toroidal mirrors (one concave-concave and the other concave-convex), providing high spectral and spatial uniformity at the wafer plane. The image produced is a thin horizontal line, suitable for exposing a 25 by 50 mm field compatible with 0.25 μm VLSI. We also present the current status of the beamline being constructed at CXrl utilizing these optics.

We describe the development of the scanning photoemission spectromicroscope MAXIMUM at the Wisoncsin Synchrotron Radiation Center, which uses radiation from a 30-period undulator. The article includes a discussion of the first tests after the initial commissioning.

Publisher Summary This chapter focuses on the obese strain (OS) of chickens with spontaneous autoimmune thyroiditis as a model for Hashimoto disease. The animal models that develop autoimmune diseases spontaneously parallel the human situation more closely. This is especially true for the OS chickens, which are afflicted with a spontaneously occurring hereditary autoimmune thyroiditis that resembles Hashimoto thyroiditis in most clinical, immunological, and endocrinological aspects. Immunoregulation in the OS is altered at two levels: on one hand there is an intrinsic hyperreactivity of the immune system and on the other, a disturbed interaction between the immune and the neuroendocrine system. The abnormalities intrinsic to the immune system are, for example, reflected in the increased mitogen responsiveness of T cells, the intrinsic hyperproduction of IL-2 and increased expression of IL-2R, the general humoral and cellular hyperreactivity against exogenous antigens, and the occurrence of autoantibodies against nonthyroid antigens, albeit in rather low frequency. T-cell hyperfunction in vitro is complemented by similar observations in vivo, such as increased antiviral responses, accelerated allotransplant rejection, and graft-versus-host reaction.

The Multiple Application X-Ray Imaging Undulator Microscope (or MAXIMUM) is a project being carried out jointly by the University of Wisconsin and the Lawrence Berkeley Laboratory. The principal mode of operation of the system is as a photoemission microscope. In this mode, the radiation from the 30-period undulator on the Aladdin 0.8 GeV storage ring is first passed through a monochromator and then focussed on a pinhole aperture. A 20X demagnified image of this pinhole is formed at the sample plane by a 2-clement microscope objective of the Schwarzschild design, whose surfaces are coated with multilayers to reflect soft x-rays (>77eV). While the diffraction limit of the microscope is around 300 A at a wavelength of 120 A, imperfections in the optics and intensity considerations limit the spatial resolution that can be obtained to about 1000 A. The sample to be studied is positioned at the focus of the microscope and the energy spectra of the emitted photoelectrons are analysed by a cylindrical mirror analyser. In this way it is possible to obtain detailed chemical maps of the specimen, with information on both its chemical components and their chemical status. In this paper we describe the design and operation of the the MAXIMUM beamline, and present some preliminary results obtained with solid state and biological samples.

For 0.25-μm lithography, the beam of x rays must display high spectral and spacial uniformity at the wafer plane. Synchrotrons provide a very stable and very well defined source of x rays. The small width of the electron beam (σ x = 675μm and σ y = 175μm —for ALADDIN operating at 800 MeV) acts as a point source, providing crisp images at the exposure plane roughly 2 m away. However, at a distance of 12 m a 1-in.-wide exposure field collects only 2.1 millirad of the available radiation. There are two ways to improve the incident power at the photoresist: shorten the line or install focusing elements. Installing focusing elements has the potential advantage of collecting x rays from a very wide aperture and providing an image that can be matched to the requirements of the exposure system. We will review the different types of beamlines proposed to date and discuss the advantages of this new design. The current status of the beam line being constructed at CXrL by using these optics will also be presented.

When measuring optical radiation due to electron and ion bombardment of alkali halides, we have observed a broadband radiation pattern whose origin is not well understood. Though CN has been suggested as a possible source [1,2], some problems with this interpretation are encountered. Conditions under which the peaks were produced and some parameters which affect their intensities are reported here. We also include a description of our attempts to determine the source of the bands.

We recently commissioned the SRC/Vanderbilt University 6‐m toroidal grating monochromator beamline. The problems with mirror heating, signal normalization, monochromator control, and scattered light reduction have led to several innovations on this line, making for a better user interface and adding to the stability and reliability of the final image. We discuss these innovations, and how they affect the user. They include a built‐in laser alignment system, a sapphire windowed gate valve, entrance mirror temperature stabilization, computer automation and control, a beam‐chopper, and the capability of real‐time monitoring of the photon flux during the experiment. We have used noble gas resonance lines to carefully characterize the wavelength resolution of the beamline as a function of energy over a range of beamline parameters. The results demonstrate that by limiting the horizontal width of the image at the slits, and by masking outer portions of the gratings, the flux/bandwidth ratio can be improved at t...

A technique has been developed for creating in the laboratory suprathermal, neutral atomic beams by means of grazing-incidence collisions between ion beams and metal surfaces. Residual ions are deflected by applied electric fields. The resulting neutral beams are pure, well-focused and mono-energetic. Energies from a few eV to tens of keV are obtainable. The technique permits the beams to be used in conjunction with electron and photon irradiation for studies of synergistic effects. Of particular interest is the creation of a low-energy, neutral, atomic-oxygen beam, which is of importance to space-related research.

The phenomena of spaceglow and material erosion, which are observed on spacecraft that orbit the earth at low altitudes, are described. Also described are the physical environment of the low earth orbit and the methods by which laboratory research on these phenomena is conducted.

A sex-linked dwarf strain of chickens fed a practical chick starter had a high incidence of rickets while other strains, including the Cornell K strain reared under the same conditions, had no evidence of this disease. In studies of the calcium, phosphorus and vitamin D requirements of the dwarf and K strains, no strain differences in requirement for phosphorus or vitamin D for maximal bone mineralization were apparent. The vitamin D requirement for growth was less for dwarfs than for the K strain; the reverse was observed for phosphorus. A marginal level of calcium (0.6%) did not depress growth or bone ash in either strain. Dwarfs had significantly lower bone ash than chicks of the K strain when dietary levels of calcium, available phosphorus and vitamin D were adequate (1.0%, 0.73% and 400 I.U./kg., respectively). When the diet contained a low level of one nutrient (0.6% calcium, 0.33% of phosphorus or 100 I.U./kg. vitamin D), neither strain was affected. Low levels of two nutrients significantly decreased bone ash in dwarfs but not in the K strain. Low levels of all three nutrients depressed bone ash in both strains, but most markedly in the dwarfs. These studies indicate that chicks of the Cornell dwarf strain have a low bone mineral content and are unusually susceptible to rickets.

The average coefficient of inbreeding after 35 years of development of Cornell S strain was estimated at 39% using pedigree data. Based on the number of breeders used and assuming that all breeders were one year old, the expected coefficient of inbreeding would have been 69%. The average age of breeders used in any one year varied between 1.05 and 2.36 years. It is suggested that the smaller coefficient of inbreeding was primarily the result of a decrease in the number of generations possible in the fixed time span of 35 years when the average age of breeders was greater than one year.

Genetic effects on spontaneous autoimmune thyroiditis in chickens were assessed by measuring phenotypic symptoms, the titer of circulating antibody to thyroglobulin, and the pathological change in the thyroids of young chicks. One or more loci within the B complex (the major histocompatibility complex of the chicken) are responsible for the expression of autoimmunity, and evidence is provided for an interaction of the B haplotype with genes at other loci. The influence of the B complex component on genetic susceptibility is more visible in animals with limited susceptibility at other loci and becomes indistinguishable as the frequency of other genes determining thyroid autoimmunity increases.

The discovery that neutral excited- and ground-state atoms are efficiently desorbed from alkali halide surfaces by both electrons and photons has raised a host of questions about the ways in which energy is absorbed, localized and redistributed in electronically-stimulated desorption. We present recent measurements of electron- and photon-stimulated desorption of neutral alkali atoms from LiF and NaCI which attempt to answer these questions by providing details of energy dependence, velocity distributions and variations in the desorption yield as a function of surface temperature. The ground-state neutral desorption dynamics under both electron and photon irradiation are consistent with a model in which halogens are ejected from the surface in a focused collision sequence, while the neutral alkalis are desorbed thermally. However, the excited-state neutrals do not follow this pattern, and further measurements to understand excited-state neutral desorption will be necessary. The implications of the experimental data for an understanding of the desorption mechanism-such as correlations with specific core-level excitations and with mobilities of electronically-induced defects-will be discussed.

INTRODUCTION WHILE there is general agreement that some degree of heterosis is to be expected from crossing different breeds, and also from crossing inbred strains of one breed, there is still much to be discovered about (1) the ways in which that heterosis may be shown and (2) the amount of inbreeding of parent strains that is necessary to induce it. This report presents some evidence on both of these points. It comes from reciprocal crosses made in two successive years between two strains of White Leghorns which, although maintained for some years as distinctly separate strains, were only slightly inbred. STRAINS CROSSED The Leghorns crossed were of the C-Resistant and K-Resistant strains which, since 1935, have been bred by the authors for resistance to leucosis and, concurrently, for increased egg production, for eggs of about 58 to 60 grams, and for a body weight of about 2,000 grams. Details . . .

THE size of the comb in different breeds bears no direct relationship to the inherited ability to live and to lay. However, within any one breed the extent to which a rather large comb might interfere with feeding or be more prone to injury could indirectly affect a bird’s health or production. Dubbing to improve a cock’s chances in the fighting pit has been practised for a long time, and in colder climates males are often dubbed to eliminate the adverse effects of a frozen comb and wattles on vigor and fertility. It is surprising, therefore, that the dubbing of females has not received consideration until recent years. Perhaps the first attempt to evaluate the effects of dubbing females was that of an unknown poultryman who reported his findings in the Australian Poultry World. These were summarized subsequently by the Editor of the New Zealand Poultry World (Anonymous, 1942). In …

HUTT and Scholes (1941) have shown that adult White Leghorns are significantly more resistant to pullorum disease than are the adults of heavier breeds such as Rhode Island Reds, Wyandottes, and Barred Plymouth Rocks. Furthermore, they showed that newly-hatched White Leghorn chicks display a greater resistance to pullorum disease than do chicks of the Rhode Island Red and Barred Plymouth Rock breeds. This resistance is undoubtedly accompanied by some physiological or morphological phenomenon which the White Leghorn breed possesses to a greater degree than the heavy breeds. Schnetzler and Hartsell (1940) have reported that adult White Leghorns and Rhode Islands Reds differ in the bactericidal power of the sera of their blood. They found that the more resistant Leghorns had greater bactericidal power and suggested that this greater bactericidal action on the part of the sera of the White Leghorn fowl might account, at least in part, for the greater . . .

SUMMARY Blood sugar, the serum concentration of total lipids, total glycerol, cholesterol and phosphatides were determined in chickens from the Obese strain (OS) of White Leghorns. Over 90% of these chickens are afflicted with a spontaneously occurring autoimmune thyroiditis and show clinical symptoms of hypothyroidism. Blood glucose levels were increased above normal limits in OS chickens up to 5 weeks of age. Significantly increased serum lipid concentrations were found in the OS chickens at the ages of 1, 5, 8 and 15 weeks, while 3-week-old OS chickens showed almost normal serum lipid levels. A single intravenous injection of heparin in a dose which prolonged bleeding time, had no 'clearing effect' on the serum of OS birds. Insulin given subcutaneously for 4 days had no effect on blood sugar but decreased the serum phosphatides and total lipid concentrations. The short-term administration of high doses of thyroxine significantly lowered the serum levels of total lipids, cholesterol, phosphatides and total glycerol.

IN RECENT years considerable attention has been drawn to a newly recognized genus of gram-positive organisms which apparently is responsible for a variety of pathological conditions affecting several species of animals, including man. In some species the organisms of the genus Listeria show a predilection for the central nervous system where they produce an encephalitis or encephalomyelitis. The literature on this subject has been recently reviewed in several papers, one of the latest of which is by Graham, Hester, and Levine (1940). The organisms of this genus have been associated with fatal infections of the central nervous system and its coverings in man, sheep, cattle, goats, and foxes. Organisms of this genus were first described under the name of Bacterium monocytogenes by Murray, Webb, and Swann (1926) as the etiological agent of a disease of rabbits which was characterized by a monocytosis. Recently some evidence has been accumulated to indicate . . .

THE diagnosis of blue comb on the basis of clinical symptoms, and gross and microscopic lesions, is fairly definite when the disturbance involves several birds in a population. It is much less so when only an individual bird is available for autopsy and the case history does not indicate a generalized flock condition. Blue comb, as a specific disease entity, has been recognized for several years and can cause considerable loss in the form of mortality, reduced production, and often from the failure of laying flocks to regain previous levels of performance. It apparently is not limited to any age group or season of the year, although many of the outbreaks occur among maturing pullets during the hot summer weather. CASE HISTORY Blue comb, as such, has not been a problem in the departmental flock at Cornell University for several years. About 1940, this disease affected newly-housed White Leghorn pullets, . . .

OVULATION and the subsequent laying of a normal egg, usually within 26 hours, are preceded and accompanied by certain changes in the body of the hen. The external characters that are associated with an active state of egg production are well known and are used as the basis for the periodic culling of commercial laying flocks. By the absence of external changes considered indicative of egg production, one is able to identify non-layers and to remove them from the flock, if so desired. It is customary to consider as layers those birds which show the external characteristics associated with egg production. We have learned, however, that some birds behave as though they were laying, and show appropriate changes in body condition, without actually producing an egg. This paper presents the pertinent findings when groups of such birds were subjected to study. SOURCES OF DATA Among large populations of pedigreed White …

The incidence of ventricular fibrillation during and after temporary experimental occlusion of the left anterior descending coronary artery or its branches was studied in 351 dogs. A standardized procedure of thirty-minute temporary occlusion of this artery was employed in 330. There is usually a critical period after twelve and up to fifteen minutes of ischemia which is characterized by a tendency to arrhythmia: extrasystoles, singly or in runs, ventricular tachycardia, or both extrasystoles and tachycardia if not a fatal ventricular fibrillation. Several instances of transient ventricular fibrillation were observed. Of 239 animals surviving thirty minutes of occlusion, 71 per cent developed ventricular fibrillation immediately after release of the artery, while only 28 per cent of 330 animals developed fibrillation during the occlusion. The re-establishment of blood flow to an area of the myocardium made ischemic for thirty minutes by occlusion of the anterior descending coronary artery is more likely to precipitate ventricular fibrillation than is the period of ischemia itself. Various drugs were evaluated in 324 dogs. Quinidine was the most effective drug in affording protection from ventricular arrhythmia during (7 per cent) and following (47 per cent) occlusion. Procaine, procaine amide and Apresoline offered good protection during the ischemic period. Apresoline and Regitine also reduced the incidence (44 and 37 per cent) of ventricular fibrillation upon reopening the ligature. Of the other drugs tested, only one, pendiomide, showed significant protection (52 per cent incidence). Systemic arterial pressures did not predict the onset of ventricular arrhythmia. Electrical countershock accomplished cardiac resuscitation in 75 per cent of the fibrillating dogs. From these experiments, quinidine appears to be the drug of choice in the prophylaxis of fatal ventricular arrhythmias.

DURING the first 8 years of selection at this laboratory for genetic resistance to leucosis combined with other traits of economic value, it was our practice to leave each male in his breeding pen throughout the entire hatching season of 8 to 10 weeks. By 1942 it was evident that, while marked improvement had been made in the first three years, progress thereafter had been almost nil. It was equally clear why improvement had stopped. We had tried each year to find enough good proven sires to head at least 25 percent of the breeding pens. During the first 5 years, the average number of pens used for the two resistant lines together was only 13.2, but, among the 10 cockerels or so tested annually, it was seldom possible to find 3 or 4 proven sires that could be used again without considerable misgivings. In 1940 to 1942, the average …

INTRODUCTION FOUR years ago, Hutt et al. (1941) reported results for the first four generations of White Leghorns bred for resistance to disease, particularly to lymphomatosis. These showed that, whereas deaths from neoplasms during the test period were 16 percent in the unselected population with which the experiment started, in the fourth generation such deaths had been reduced to 12 percent. This decrease, really by a quarter of the original proportion, seemed significant, not merely because it was based on 785 birds, but because, at the same time, deaths from neoplasms were more than twice as frequent (26 percent) in the stock bred for susceptibility. Moreover, the decline of total mortality from 64 percent in the unselected population to 38 percent in the fourth generation permitted a higher proportion of the latter to develop neoplasms had they been genetically susceptible. The fact that only 12 percent did so is more . . .

AS YET there is no critical evidence to show definitely that the agent of avian leucosis is or is not transmitted through the egg. There has, however, been accumulated considerable circumstantial evidence to support both possibilities, especially the former concept. This is not unexpected, because positive data are more likely to be published than are negative data. It is obvious that for a complete understanding of the avian leucosis complex more information as to the possibility of egg-borne transmission of the etiological agent must be provided. In order for the disease to develop, two conditions must be satisfied. The infective agent must be present and the host must be genetically susceptible. Natural (genetic) resistance is a relative factor and its normal expression can be overridden by an excess of the agent or exposure. Such happenings occur regularly and are responsible for variations in incidence of the disease within a flock . . .

Immunologic findings in the Obese Strain (OS) of chickens are described. This strain was obtained by selective breeding of individual OS chickens which comprised less than 1% of the original flock of the Cornell C-strain. At the present state of breeding about 80% to 90% of the individual chickens exhibit the OS characteristics. Tanned red blood cells from chicken, sheep and human coated with chicken thyroid extract are agglutinated by the majority of sera of OS chickens to various titers. Only chicken thyroid extract and no other chicken organ extract is capable of inhibiting the reaction. On the other hand, cells coated with human thyroid extract are essentially negative, showing the species-specificity of the chicken thyroglobulin antibodies. Precipitins can be easily demonstrated in the sera of OS chickens. By both methods (indirect hemagglutination and precipitation) the autoantibody nature of the thyroglobulin antibody can be demonstrated using thyroid material from the antibody-producing chicken itself. Upon sucrose gradient fractionation of OS chicken serum the highest hemagglutination titer appeared in the lighter antibody fraction and a lower one in the heavier antibody region.

It is shown that, if electrons of relativistic energies are generated within thunderstorms and then ‘run away’ upward above the thunderclouds, their range is probably only a few kilometers; their ionizing effects are therefore localized. Calculations indicate, however, that the bremsstrahlung produced during the stoppage of the electrons can create ionized columns extending to ionospheric heights (about 100 km). If the original runaways exist the bremsstrahlung must be generated, and the possibilities for their detection experimentally are considered. There appears to be a sufficient flux of Compton-scattered photons for detection at thunderhead altitudes at a few kilometers from the thunderstorm.

IN A PREVIOUS communication by one of us (F. B. H., 1938), it was pointed out that neoplasms caused over 38 percent of all deaths among 1,922 fowls dying during the six-year period, 1931–37, at two laying tests in New York. It was also shown that in this same population 87 percent of all deaths were caused by diseases thus far not amenable to control by sanitation, immunization, elimination of carriers, and other orthodox procedures currently recommended for the control of poultry diseases. Because of this situation, an experiment was begun in the spring of 1935 to test the feasibility of breeding strains of White Leghorns resistant to some of these diseases. A brief report of the first three years of this work was given earlier by Hutt, Bruckner, and Cole (1939). In the present paper, we present results of the first five years’ work. These include the unselected . . .

A study has been made of nuclear reactions in which two or more protons are emitted, in the bombardment of nickel isotopes by alpha particles. The most extensive data were obtained for 32-Mev alpha particles, with a ${\mathrm{Ni}}^{58}$ target. A smaller amount of data were obtained at 27 and 42 Mev, and with ${\mathrm{Ni}}^{60}$ and ${\mathrm{Ni}}^{62}$ targets. The two protons were observed in a coincidence arrangement, using scintillation counter $\frac{\mathrm{dE}}{\mathrm{dx}}\ensuremath{-}E$ detectors. The energy correlations and distributions, the angular correlations and distributions and the yields were compared with predictions based on the statistical theory. There was extensive agreement, and therefore it is concluded that most of the observed events arise from evaporation from an excited compound nucleus. For ${\mathrm{Ni}}^{58}$ at 32 Mev, the cross section for compound nuclear events in which two or more protons are evaporated was found to be 560\ifmmode\pm\else\textpm\fi{}50 mb which is over one third the total reaction cross section. This large cross section can be quantitatively understood in terms of the proton richness of the emitting compound nucleus. This conclusion follows from an analysis in which it is shown that the relative proton and neutron emission probabilities in other experiments (especially with 14-Mev incident neutrons) are strongly correlated with proton richness.

An attempt is made to unite the concepts of atmospheric electricity and of lower ionospheric physics by using a common theoretical approach to derive profiles of electron and ion densities from 0 to 100 km. Relations between height and the rate of ion production that apply to average geographical and temporal conditions are used, together with selected values of attachment, detachment, and recombination coefficients. The uncertainty in and range of variation of these coefficients are discussed, and some examples given of the associated variability in the derived electron and ion density profiles. Estimates of collisional frequencies are used in conjunction with the electron and ion density information to obtain profiles of conductivity versus height. Below some 40 to 50 km, ionic conductivity is dominant. Deductions regarding mobility and its relationship to ion-clustering are considered. It is demonstrated that when ionization is being produced below about 40 km, the radio wave absorption due to ions is much more important than that caused by electrons. It is also shown that any effects on atmospheric electricity observations at the ground associated with ionizing fluxes in the upper atmosphere are probably due to stratospheric space charges rather than to changes in conductivity at high altitudes. The applications of the conductivity profiles to radio wave propagation at VLF and ELF are briefly examined.

DURING the last three decades considerable work has been expended in an effort to characterize the enzyme lysozyme and its action, details of which can be found in the excellent reviews by Thompson (1941) and Hartsell (1949). Although the egg white of the domestic fowl has long been accepted as a highly concentrated source of the enzyme, the variation existent in the egg white of different hens has not received attention. Indeed, some workers have used egg white as a standard reference in their quantitative measurements of lysozyme in other fluids and tissues. Recent evidence (Hawthorne, 1950; Feeney et al., 1952) suggests a primary role of lysozyme in the thinning of the egg white. All other avian species that have been tested thus far (Fleming and Allison, 1924; Smolelis and Hartsell, 1951) have been shown to have less lysozyme in the whites of their eggs than has the domestic fowl… .

THE persistent claim by Waters (Waters and Prickett, 1944; Waters, 1945; 1947) that avian leucosis is spread by transmission through the egg to the chick has now been extended to include a theory that chicks are infected in the incubator by dissemination there of the causative virus (Waters and Bywaters, 1949). These themes have received so much attention by the world’s poultry press that many poultrymen are now hoping to be able eventually to control the disease by the detection and elimination of hens carrying the virus or by disinfection of the incubator. In our opinion, the data presented hereunder show (1) that it is very unlikely that the disease is transmitted through the egg, (2) that any such transmission that may occur is of no significance whatever in the practical control of leucosis, and (3) that the all-important factors in determining the severity of this disease in a flock . . .

THE use of multiple shifts for testing large numbers of cockerels has proven of value as a method for recognizing superior sires (Hutt and Cole, 1955). Males proven to be superior by performance of approximately 50 daughters are then used in subsequent years throughout an entire breeding season of 8 to 9 weeks and produce families two to four times as large. The chief objection to the shifting or replacing of males in the breeding pens is that for a period of time the paternity of the chicks hatched may be in doubt. In practice, this uncertainty need not be a deterrent to the use of multiple shifts. The actual error in assignment of paternity is so low that it would not influence the evaluation of either parent. PREVIOUS REPORTS Crew (1926) exchanged males in two breeding pens and measured the speed with which the semen of the replacing male …

THE relationship between the iris color of the dam and mortality of her progeny is of considerable interest to the poultry breeder. This interest is prompted by the fact that an association of abnormal iris color of the dam and a high rate of mortality of the progeny would offer an immediate, practical means of reducing mortality. One of the most comprehensive studies of the subject has been that of Lee and Wilcke (1941). They demonstrated that females with pearl-gray irises which were irregular at the pupillary border gave progeny which developed symptoms of fowl paralysis more frequently than did the dams with normal eyes. This suggested that such females were transmitting the causative agent of lymphomatosis through the egg to the chick. Earlier, McClary and Upp (1939) had found that dams which were affected with iritis had a greater proportion of daughters with iritis than did dams with unaffected . . .

IT IS now generally recognized that there are two distinctly different means of reducing mortality in fowls from lymphomatosis and related diseases. One of these is to breed strains that are comparatively resistant. The feasibility of doing so has been demonstrated by Hutt et al. (1941) and by Taylor et al. (1943), but the utilization of this method is limited by the fact that few poultrymen are in a position to maintain the necessary exposure to the disease and to carry out over a period of years the progeny testing, with its inevitable record keeping, that is required in breeding of this kind. The other method is to rear the chicks in complete isolation from adult fowls during the growing period. The efficacy of this procedure was demonstrated experimentally by Kennard and Chamberlin (1936) and by Johnston and Wilson (1937). It has been confirmed in practice by many poultrymen. Disadvantages . . .

The properties of a quantum hard-sphere gas in the limit of high densities are investigated, with particular emphasis on the ground-state energy per particle. This has the asymptotic form $\frac{{E}_{0}}{N}{}{\ensuremath{\sim}}{\ensuremath{\rho}\ensuremath{\rightarrow}{\ensuremath{\rho}}_{0}}\frac{{\ensuremath{\hbar}}^{2}}{2m}A{({\ensuremath{\rho}}^{\ensuremath{-}\frac{1}{3}}\ensuremath{-}{{\ensuremath{\rho}}_{0}}^{\ensuremath{-}\frac{1}{3}})}^{\ensuremath{-}2},$ as deduced from the Heisenberg principle, and is independent of particle statistics. A model of hard spheres arranged in a simple cubic lattice is solved by reduction to the known one-dimensional case, and gives ${A}_{\mathrm{sc}}={\ensuremath{\pi}}^{2}$. For more realistic close-packed systems we estimate ${A}_{\mathrm{cp}}\ensuremath{\approx}10 \mathrm{to} 15$. This form connects smoothly to the well-known low-density gas-parameter expansions. Phonon properties in the Debye approximation are derived. The model is applied to the zero-point kinetic energies of hexagonal-centered-cubic (hcp) $^{3}\mathrm{He}$, $^{4}\mathrm{He}$, ${\mathrm{H}}_{2}$, and ${\mathrm{D}}_{2}$, as determined from pressure data. The helium data give $A\ensuremath{\approx}15.7$, the hydrogen data $A\ensuremath{\approx}15.9$. The fitted hard-core diameters, 1.73 \AA{} and 1.90 \AA{}, respectively, are smaller than expected from accepted potentials; this is discussed. Thermodynamics of the simple cubic system give ${c}_{v}\ensuremath{\propto}T$ for both bosons and fermions, which may explain the anomalous (non-Debye) heat capacitics of solid $^{3}\mathrm{He}$ and $^{4}\mathrm{He}$ at low temperatures.

NORMALLY the hen will surround with egg albumen and enclose within shell any object of a sufficient size (mature ovum) which passes down the oviduct. In the normal physiological process of egg production the mature ovarian follicle ruptures along the stigma; the released ovum is then engulfed by the infundibulum and as it passes down the oviduct acquires the various layers of egg albumen, shell membranes, and shell. Through some fault in ovulation, weakness in ovarian structure, or excessive physical tension, an intrafollicular ovum may be released or torn intact from the ovary and when picked up by the infundibulum, provides the necessary stimulus for physiological activity of the oviduct. The production of double-yolked eggs containing, in addition to the normal ovum, an intrafollicular ovum with stalk protruding through the shell at the larger end of the egg have been reported by Laboulbene (1859) and Hutt (1946), who also cited . . .

THE remarkable prophylactic and therapeutic value of sulfonamide drugs against certain types of bacterial and protozoan diseases has been amply demonstrated in the domestic fowl. It is not surprising, therefore, that these drugs have been used against pullorum disease by several investigators. Severens, Roberts, and Card (1945) found that certain of the drugs, namely sulfadiazine and sulfamerazine, were quite effective in controlling mortality following the oral inoculation of day-old chicks with broth cultures of S. pullorum, even though feeding of the drugs was delayed for 3 days after inoculation. Similar results have been obtained by Bottorff and Kiser (1947) who fed the drugs for varying periods of time, starting with the day of inoculation. That sulfonamides can be of practical value under field conditions in which the disease has progressed far enough to cause losses and at least the presumptive diagnosis of pullorum disease obtained has been shown by Anderson . . .