280 



The Journal of Heredity 



recounted here. Suffice it to say that 

 Bateson leaves one in a very critical 

 state of mind regarding Kammerer's 

 claims. On the other hand, McBride, 

 the English zoologist, gives credence 

 to Kammerer's published results, and 

 claims that Bateson is too severe with 

 him. Nevertheless, it is the privilege, 

 and even the duty, of scientists to 

 maintain an attitude of skepticism on 

 crucial results. Pending a better un- 

 derstanding of all the features of 

 Kammerer's experiments, and inde- 

 pendent repetition of them, an open 

 mind is all that may be rightfully de- 

 manded of anyone. 



Another experiment now in progress 

 in the United States bears on this 

 problem. Guyer and Smith, of the 

 University of Wisconsin, injected emul- 

 sified lenses of the eyes of rabbits into 

 hens. Afterward they took the blood 

 serum of the hens, presumably contain- 

 ing rabbit lens anti-bodies and injected 

 it into the blood stream of pregnant 

 rabbits. When the young of these rab- 

 bits were born a few of them were 

 found to have various degrees of de- 

 fective lenses, the lenses having been 

 almost eliminated in some cases. These 

 lens defects have been inherited through 

 several generations, through the male 

 as well as the female parent. It ap- 

 pears that the anti-lens substance 

 acted not only upon the lenses of the 

 developing rabbit fetuses, but also on 

 the germ plasm ; or it acted on the 

 lenses which in turn ]:)roduced some- 

 thing that acted on the germ plasm. 



This experiment, conducted by biol- 

 ogists of such integrity and training 

 has aroused great interest. While 

 as in almost all things, there is room 

 for criticism of some phases of the 

 experiments, nevertheless great hope 

 of real progress in this field has 

 s])rung up. 



That nurture may often have tre- 

 mendous influence on the nature that 

 has been inherited is made manifest 

 in many ways, as illustrated by the 

 efifects of nutrition, poisons, heat and 

 light, abrasions, friction, exercise, and 



so forth. Most people assume without 

 question that such effects are inherit- 

 ed. Thousands of volumes could be 

 crowded with the anecdotal evidence 

 supposed to exemplify such inherit- 

 ance. There are also the efforts of 

 the scientists, many more than those 

 that I have recounted. Ne\erthe- 

 less none of these accounts, nor 

 the experiments, leave us quite cer- 

 tain that any such effects recur from 

 generation to generation without the 

 recurrence of the affecting agencv. 

 What an anomaly that with the abund- 

 ant opportunities for observation not 

 one single alleged case of the inherit- 

 ance of acquired characters, or the in- 

 duced mutation of the bearers of the 

 heritage, can as yet be accepted with 

 complete conviction. 



That is, if the materials and condi- 

 tions recorded as used in the experi- 

 ment were duplicated we have no 

 assurance that similar results would 

 be obtained by independent workers. 

 Until such unquestioned duplication of 

 results are obtained by others using 

 the same, or similar methods, the bril- 

 liant experiments of Brown-Sequard. 

 Tower, Kammerer, and Guyer and 

 Smith can hardly be accorded a posi- 

 tion of greater consequence than that 

 of harbingers of promise, and stimu- 

 lates to further effort. 



An effort has been made to present 

 the most striking results tending to 

 show that the effects of the environ- 

 ment may be transmitted. The tenta- 

 tive conclusion reached, at least by 

 the speaker, is that entirely satisfac- 

 tory proof has not been forthcoming. 



The Immutability of the Germ Plasm 



Now let us examine some of the evi- 

 dence which indicates how difficult it 

 is to influence the germ plasm by im- 

 ])ingement with the environment. One 

 line includes ovarian transplantation, 

 another, identical twinning, and the 

 third, Mendelian heredity. 



The physiologist, Hea])e, took the 

 fertilized egg of the long-haired, white 

 Angora rabbit before its im])lantation 



