. The Journal of experimental zoology. is well established, moreover, that certainpathogenic agents may traverse the placenta and produce ante-natal infections. In our experiments, that all the young were not invaded, orthat they were unequally invaded, or that being invaded somewere more resistant than others to the influence of the antibodies,is evident from the fact that a very substantial majority of thetotal number of young obtained showed no specific effect of thetreatments. It is not impossible that in the struggles of themothers, slight breaking down of the walls of the placental blood
. The Journal of experimental zoology. is well established, moreover, that certainpathogenic agents may traverse the placenta and produce ante-natal infections. In our experiments, that all the young were not invaded, orthat they were unequally invaded, or that being invaded somewere more resistant than others to the influence of the antibodies,is evident from the fact that a very substantial majority of thetotal number of young obtained showed no specific effect of thetreatments. It is not impossible that in the struggles of themothers, slight breaking down of the walls of the placental blood-vessels occurred in some cases, permitting some direct flow of thematernal blood into the fetus. And it may be that only suchfetuses got a sufficient amount of the lens antibodies to have theirown lenses affected. But whatever the means, the importantfact is that penetration was accomplished in some way, with theresult that defective-eyed offspring were occasionally produced. 200 M. F. GUYER AND E. A. SMITH (U CC I -u I2; .e ■-5 03. bfl Oi 0) F—; ^ n; mO m -i-i •o .2m 03 03 r-*^ C -C 02 1=1o3 a; ^5 +3 +3 0 ;h «4-l <1) s^ c: ^^ *\) <^ TRANSMISSION OF INDUCED EYE-DEFECTS 201 TRANSMISSION OF THE DEFECTS THROUGH BREEDING Perhaps the most interesting and important result of our ex-periments is the estabUshment of the fact that the defects, oncesecured, may be transmitted to subsequent generations throughbreeding. So far, we have succeeded in passing the condition tothe sixth generation, and there seems to be no reason why itwill not go on indefinitely, since the imperfection tends tobecome worse in succeeding generations and also to occur in aproportionally greater number of the young. At present we have thirty-seven living individuals withmarkedly abnormal eyes. Many more could have been securedif all the defective-eyed animals had been mated as frequentlyas possible. Up to the present, however, our chief aim has beento pass the defect through as many successive gene
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