The First International Eugenics Congress / by Edgar Schuster.

  • Schuster, Edgar.
Date:
[1912]
Catalogue details

Licence: In copyright

Credit: The First International Eugenics Congress / by Edgar Schuster. Source: Wellcome Collection.

    4/36 (page 4)
    Persons who are really normal are called duplex. They have the normal development determiner twice over, or are homozygous with regard to its presence. If this theory is correct, then when nulliplex is mated with nulliplex, one would expect to find the offspring all nulliplex. That is to say that the children of parents who are both feeble-minded or epileptic should all be feeble-minded or epileptic themselves. An examination of the tables shows that there are a considerable number of exceptions to this rule, but the obvious difficulty of classifying all cases correctly may account for them. On the whole it may be said that the results are not incompatible with the theory. With regard to the other types of matings Dr. Weeks cannot claim a very close agreement between the actual results and the theoretical expectation. Difficulties of classification may be again called in to account for the discrepancy, and in addition two other factors. One of the two is suggested by the author, namely, that the percentage of nulliplex (i.efeeble¬ minded or epileptic) among the offspring, where it is, as it generally is, in excess of the mendelian expectation, has been increased by the direct action of parental alcoholism. But there is another and more obvious explanation which he does not appear to have taken into account, namely, the manner in which the material was collected. This has had the effect that almost all the fraternities considered contain at least one epileptic. Thus the composition of the chosen families cannot be taken to represent fairly what would be the character of the offspring of matings of the various classes considered, if the parents had been selected entirely according to their own characteristics and not partly on account of the fact that in most cases one of the children was an epileptic. It must be allowed that a good primd facie case has been made out for the theory advocated by Dr. Weeks, a theory which if fully established would be a very distinct step in advance in the study of the inheritance of epilepsy. That it only covers a small part of the ground he would, no doubt, be the first to acknowledge. There must be some difference in the germ-plasm to differentiate such very different conditions as