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Summary Minor changes in procedure of preparing and mixing egg yolk media were found to have a marked effect on the settling of egg yolk and semen plasma solids. The visible settling of egg yolk and semen plasma solids during the storage or shipping of a diluted specimen of bull semen apparently has no influence on the duration of motility or survival of the spermatozoa. The sedimentation rate of the spermatozoa in most of the common semen-diluting media is very rapid under storage conditions. Apparently, at storage temperatures, the minute spermatozoa are behaving as inert particles, since the sedimentation rates of live and of dead cells were almost identical. In view of the rapid sedimentation rate of spermatozoa during storage, a diluted semen specimen should be thoroughly mixed prior to evaluation by the usual techniques or to utilization for artificial insemination. The evidence presented indicates that the rapid sedimentation of the spermatozoa during storage does not affect spermatozoan survival.

Summary Semen specimens from healthy dairy bulls were extended with six diluents, stored at 4 to 7° C. and examined daily for both motility and freezing point depression. One of these diluents, the egg yolk-citrate diluter, failed to maintain the osmotic pressure of the extended semen within the range suggested by Pursley and Herman as optimal for semen diluters. The other diluents used in commercial artificial insemination did maintain the osmotic pressure within these limits, and one of these, the egg yolk-glucose-NaHCO 3 diluter developed by Kampschmidt et al. (7) , maintained the osmotic pressure along the line of mean freezing point depression of semen, a point further strengthened by its superior motility maintenance during the storage period. It is suggested that added glucose aids in the maintenance of storage osmotic pressure within narrow limits and thus may have an influence upon the viability of bull spermatozoa during a prolonged storage period.

ALTHOUGH the literature is replete with studies of the concentrations and in terrelations of the hormones during the physiological state of pregnancy in A. JV the mare, investigationsinvolving similar studies during the various phases of the estrous cycle of the non′pregnant mare are rare. Zondek (I) reported comparative data upon the estrogenic hormones in the urine of the pregnant and non-pregnant mare, and more recently Cole and Goss (2) cited the presence of gonad tropic hormone in the blood of the latter. However, nowhere in the literature are studies available upon the estrogens of the urine or follicular fluid in relation to the various phenomena of the estrual cycle. For periods beginning in February or April and ending about the middle of July of the years 1937,1938, and 1939 detailed studies were made in the physiology of the non-pregnant mare at the United States Range Live-Stock Experiment Station, Miles City, Montana.

CONTRIBUTIONS to the knowledge of the influence of reproduction, especially that of the individual reproductive hormones upon the growth rate in the female, have not been numerous. In most of these investigations the effects of ovariectomy or of pregnancy were generally studied. Evidence that ovariectomized rats grow more rapidly than virgin controls has been presented by Stotsenburg (1913), Slonaker (1930), Freudenberger and Billeter (1935), Freudenberger and Howard (1937), Freudenberger and Hashimoto (1937–38 and 1939) Bogart et al. (1940), and Tang (1941). Pronounced differences in the rate of growth were shown to exist between pregnant and virgin female rats of the same age by Slonaker (1927), Cole and Hart (1938) and Bogart et al. (1940). The effects of pregnancy, pseudopregnancy (Hart and Cole, 1939) and ovariectomy upon growth indicate that the reproductive hormones may be directly or indirectly involved.

Summary The effect of whole egg yolk and its constituents upon the dehydrogenase activity of bovine spermatozoa was determined. Whole egg yolk was found to stimulate the succinic, malic, and glyceraldehyde-3-phosphate dehydrogenase activity of these cells. The dehydrogenase-stimulating effect of egg yolk was found to be associated with the acetone-soluble fraction of the yolk and appeared to be the result of the stimulatory effect of cholesterol and of carotene upon succinic dehydrogenase activity. Cholesterol was observed to inhibit both glyceraldehyde-3-phosphate and malic dehydrogenase activity of bovine spermatozoa. The importance and possible mechanisms of dehydrogenase stimulation and inhibition by egg yolk, cholesterol, and carotene have been discussed, as well as the apparent failure of lecithin to stimulate succinic dehydrogenase activity.

Summary The effect of season upon the succinic dehydrogenase activity of bovine spermatozoa has been investigated by a manometric method. Succinic dehydrogenase activity of bovine spermatozoa has been found to vary in a manner which was significantly correlated with the mean monthly temperatures as obtained from the local weather bureau. The effect of washing upon the succinic dehydrogenase activity of bull spermatozoa was found to be seasonally dependent, as well. These observations have been discussed in relation to their importance to research in the physiology of reproduction, and to the application of reduction tests as a measure of semen quality.

Summary. Five major phospholipids of ejaculated and epididymal porcine spermatozoa were separated and quantitatively determined by thin-layer chromatography. These were in the order of decreasing concentration, phosphatidyl choline, phosphatidyl ethanolamine, ethanolamine plasmalogen, sphingomyelin and choline plasmalogen. Phosphatidyl serine, lysolecithin and possibly phosphatidyl inositol were also present, but in low concentrations. The concentration of phosphatidyl choline and phosphatidyl ethanolamine in spermatozoa progressively decreased from the head to the tail of the epididymis, and was lowest in ejaculated semen. The plasmalogen content of spermatozoa from all levels of the reproductive tract of the boar was low and varied very slightly.

SummaryNone of the fractions obtained from porcine spermatozoa resembled the classical histones or protamines in amino acid content when two different isolation procedures were utilized. A physical attack on the keratin by glass beads appeared to give inadequate penetration to release the other proteins of this cell. A chemical attack with per formic acid appeared quite adequate. Much of the protein in this cell is a basic keratin. The properties of such a protein would allow it to protect the DNA during its journey to the ovum.

A modified silicic acid technique was developed for separation of the lipids of bovine spermatozoa into seven distinct classes: saturated hydrocarbons, cholesterol esters, free cholesterol, triglycerides, diglycerides, monoglycerides, and phospholipids. The average lipid content of lyophilized spermatozoa was 11.05%. Monoglycerides and diglycerides were found in exceptionally large quantities, but no unsaturated hydrocarbons of free fatty acids could be detected.

AN alkali-soluble protein fraction, obtained from calf thymus nuclei, was reported by Mayer and Gulick1. Upon addition of acid to the alkaline solution, precipitation of this fraction occurred at about pH 6. Stedman and Stedman2,3 obtained an alkali-soluble protein fraction, ‘chromosomin’, from several kinds of nuclei, including the heads of fish spermatozoa. Alkali-soluble protein fractions, which are precipitated when the solution is made acid, were recently reported to be present in boar spermatozoa4.