Ovize, Fêrê and Stockard have shown that the effect of alcohol on hen's eggs is to produce malformed embryos. This, however, is a case of influencing the development of the individual, rather than the germ-plasm. Evidence is abundant that individual development can be harmed by alcohol, but the experiments with eggs are not to the point of our present purpose.
Carlo Todde and others have carried out similar experiments on cocks. The conclusions have in general been in favor of injury to the germ-plasm, but the experiments were inadequate in extent.
Laitinen experimented on rabbits and guinea pigs, but he used small doses and secured only negative results.
Several series of experiments with rats indicate that if the dosage is large enough, the offspring can be affected.
Nice, using very small numbers of white mice, subjected them not only to alcohol, but to caffein, nicotin, and tobacco smoke. The fecundity of all these sets of mice was higher than that of the untreated ones used as control; all of them gained in weight; of 707 young, none was deformed, none stillborn, and there was only one abortion. The young of the alcoholized mice surpassed all others in growth. The dosage Nice employed was too small, however, to give his experiment great weight.
At the University of Wisconsin, Leon J. Cole has been treating male rabbits with alcohol and reports that "what appear to be decisive results have already been obtained. In the case of alcoholic poisoning of the male the most marked result has been a lessening of his efficiency as a sire, the alcohol apparently having had some effect on the vitality of his spermatozoa." His experiment is properly planned and carried out, but so far as results have been made public, they do not appear to afford conclusive evidence that alcohol originates degeneracy in offspring.
The long-continued and carefully conducted experiment of Charles R. Stockard at the Cornell Medical College is most widely quoted in this connection. He works with guinea-pigs. The animals are intoxicated daily, six days in the week, by inhaling the fumes of alcohol to the point where they show evident signs of its influence; their condition may thus be compared to that of the toper who never gets "dead drunk" but is never entirely sober. Treatment of this sort for a period as long as three years produces no apparent bad effect on the individuals; they continue to grow and become fat and vigorous, taking plenty of food and behaving in a normal manner in every particular. Some of them have been killed from time to time, and all the tissues, including the reproductive glands, have been found perfectly normal. "The treated animals are, therefore, little changed or injured so far as their behavior and structure goes. Nevertheless, the effects of the treatment are most decidedly indicated by the type of offspring to which they give rise, whether they are mated together or with normal individuals."
Before the treatment is begun, every individual is mated at least once, to demonstrate its possibility of giving rise to sound offspring. The crucial test of the influence of alcohol on the germ-cells is, of course, the mating of a previously alcoholized male with a normal, untreated female, in a normal environment.
When the experiment was last reported,[16] it had covered five years and four generations. The records of 682 offspring produced by 571 matings were tabulated, 164 matings of alcoholized animals, in which either the father, mother, or both were alcoholic, gave 64, or almost 40%, negative results or early abortions, while only 25% of the control matings failed to give full-term litters. Of the 100 full-term litters from alcoholic parents 18% contained stillborn young and only 50% of all the matings resulted in living litters, while 47% of the individuals in the litters of living young died soon after birth. In contrast to this record 73% of the 90 control matings gave living litters and 84% of the young in these litters survived as normal, healthy animals.
"The mating records of the descendants of the alcoholized guinea pigs, although they themselves were not treated with alcohol, compare in some respects even more unfavorably with the control records than do the above data from the directly alcoholized animals." The records of the matings in the second filial generation "are still worse, higher mortality and more pronounced deformities, while the few individuals which have survived are generally weak and in many instances appear to be quite sterile even though paired with vigorous, prolific, normal mates."