424 EVOLUTION, GENETICS, AND EUGENICS 



ing the lens of the living female rabbit by "needling" in situ, anti-lens 

 serum has been produced in the blood of these animals. This material 

 was as effective in preventing the development of lenses in some of the 

 fetuses of these mothers as was the material produced by more elabo- 

 rate serological methods. Also the effects seem to be inherited in the 

 same way as in the former experiments. It should be noted that 

 Guyer is very cautious in his statements and makes no claim that his 

 work demonstrates the inheritance of acquired characters. He realizes 

 that the same specific material that is supposed to inhibit the develop- 

 ment of eye structures in the young fetus might readily at the same 

 time exert a specific influence upon the genes or factors for eye struc- 

 tures in the primordial germ cells that live contemporaneously with 

 the somatic structures. Thus two generations might be affected 

 simultaneously — a case of parallel induction. 



Every important experiment in science becomes the target of 

 attack, and the experiments of Guyer and Smith are no exception. 

 Bagg and Hanson and Little have performed some very interesting 

 experiments on the effects of radium emanations and of X-rays on 

 mammalian germ cells, and Stockard has used alcohol in the same way. 

 All of these workers show that eye defects, especially lens defects, are 

 found most commonly, occurring sometimes in the entire absence of 

 other observable defects. It would seem, then, that eye defects are 

 fa,r from being specific, and they may not be specific in the experiments 

 of Guyer and Smith. There is no question but that the eye is the most 

 susceptible part of the organism and that eye defects can be induced in 

 vertebrates by almost any kind of inhibiting agent. It was only when 

 Guyer used the lens material, however, that he got lens defects; for 

 when he used sera developed from other tissues no effect upon the lens 

 was noted. But no effect upon any other tissue was noted, seeming 

 to show that no effective antigens of any sort were formed. It is im- 

 possible at the present writing to predict what will be the final bearing 

 of Guyer's and Smith's very significant experiments upon the problem 

 of the inheritance of acquired characters. 



Griffith and Detlefson have recently reported some experiments 

 upon mice that at first seemed almost crucial for our problem. Rats 

 were reared for several months in cages placed upon rotating tables. 

 They became adapted to the rotating condition to such an extent that 

 when the rotation was stopped they seemed upset, showing signs of 

 nystagmus (dizziness) and other symptoms of a changed physiological 

 condition. Some of the young born outside the cages showed irregulari- 



