Elizabeth M. Lord

Heavy alcoholization and prenatal mortality in mice

Summary Brief reference is made to the more important earlier studies on the action of a utero-stimulating substance in mammals. In a small group of tests of the utero-stimulating action of a placental extract, and of a substance prepared from the liquor folliculi of the sow by the Allen-Doisy method, we have obtained a few positive results-enlargement and hyperemia of the oviduct of virgin doves. This supplies the last necessary fact in proof of the lack of specificity, as between birds and mammals, of this substance. Heavy dosage failed to affect a response in the virgin oviduct in some cases. Responses in the ovary and on sex behavior in virgin and mature doves have not been observed. An insufficient number of cases was studied but our results indicate a less ready, and a less varied, response of the bird to this substance than has been found for mammals.

The sex ratio in litters of mice classified by the total amount of prenatal mortality.

From studies of the normal sex ratio of living young and of abortions and still-births in man and the rat, King 1 and others have concluded that the male fœtus is less viable than the female. If this is true for the entire period of gestation there should be a negative correlation between the amount of prenatal mortality and the sex ratio. From counts of the corpora lutea of pregnancy of about 20 mice (sectioned material) Parkes 2 concludes that this is the case. Data showing the percent of prenatal mortality for 445 litters of mice have been obtained by subtracting the number of young born from the number of ova as indicated by the number of corpora lutea. In the last week of pregnancy the corpora lutea corresponding to the litter in utero are strikingly differentiated as large hyperemic bodies protruding from the surface of the otherwise pale colored ovary. These corpora were counted in the living animals under a low power binocular microscope by means of an operation which has been shown 3 to have no influence upon the fœtuses in utero or upon the subsequent reproduction. Table I gives the total number of males and females in litters classified, according to the per cent of prenatal mortality, into five classes, each 20 per cent in width. The sex ratio shows no tendency to decline as the percentage of prenatal mortality increases; the highest ratio is found in the next to highest prenatal mortality class. The small numbers in the fifth class indicate that its low sex ratio is probably not significant. These results indicate that when the total prenatal mortality is revealed there is found no selective elimination of males.

The sex ratio of mice from alcoholized fathers

Bluhm 1 and Danforth, 2 using somewhat different experimental methods, have reported a rise in the sex ratio of mice from alcohol treated fathers. However, these ratios are based on small numbers (182 ♂ : 149♀ Bluhm; 210 :164♀ Danforth) and, although the probable errors of the deviations from the control ratios (+10.60 per cent ±2.03 and +5.36 per cent ±1.99) may be taken to mean that random sampling alone is not responsible for the results, various other possible influences besides alcohol, such as season, mothers age and parity, have not been eliminated by the methods of these investigators. Moreover, Gyllenswärds 3 more completely controlled experiments with alcoholized male mice show as great a change in the opposite direction (—10.4 per cent ±3.4), and MacDowell and Lord 4 have called attention to the fact that when all question of the modification of the sex ratio by prenatal mortality was removed by using only complete litters (so judged by the number of the corresponding corpora lutea) the primary sex ratio given by litters from heavily alcoholized fathers and normal mothers (50.3 per cent males, based on 308 mice) showed no significant deviation from the primary sex ratio from normal parents (49.9 per cent males, based on 523 mice). The present report gives the sexes of 2133 mice from normal mothers by fathers given completely anesthetizing doses of alcohol fumes five days a week, beginning at the age of four weeks and continued over a year, to the end of the experiment; and 2322 mice from the same normal mothers by normal fathers, brothers of those treated. The treatment was given by inhalation, in one pint milk bottles; for each treatment 3 cc. 95 per cent alcohol was poured on a piece of atisorbent paper which was placed in the bottle with the mouse, a regular milk bottle cap inserted and the bottle inverted.