December 2, 1921] 



SCIENCE 



535 



member that if a tissue substance, blood- 

 serum, for instance, of one animal be injected 

 into tbe circulation of another, this second in- 

 dividual will tend to react by producing an 

 anti-body in its blood to antagonize or neu- 

 tralize the effect of the foreign serum. ITow 

 Professor Guyer's ingenious experiments and 

 results may be briefly summarized as follows. 

 By repeatedly injecting a fowl with the sub- 

 stance of the lens of the eye of a rabbit he ob- 

 tained anti-lens serum. On injecting this 

 " sensitized " serum into a pregnant female 

 rabbit it was found that, while the mother's 

 eyes remained apparently unaffected, some of 

 her offspring developed defective lenses. The 

 defects varied from a slight abnormality to al- 

 most complete disappearance. 'No defects ap- 

 peared in untreated controls, no defects ap- 

 peared with non-sensitized sera. On breeding 

 the defective offspring for many generations 

 these defects were found to be inherited, even 

 to tend to increase and to appear more often. 

 When a defective rabbit is crossed with a nor- 

 mal one the defect seems to behave as a Men- 

 delian recessive character, the first generation 

 having normal eyes and the defect reappearing 

 in the second. Further, Professor Guyer 

 claims to have shown that the defect may be 

 inherited through the male as well as the fe- 

 male parent, and is not due to the direct trans- 

 mission of anti-lens from, mother to embryo 

 in utero. 



If these remarkable results are verified, it 

 is clear that an environmental stimulus, the 

 anti-lens substance, will have been proved to 

 affect not only the development of the lens 

 in the embryo, but also the corresponding fac- 

 tors in the germ-cells of that embryo ; and that 

 it causes, by originating some destruictive 

 process, a lasting transmissible effect giving 

 rise to a heritable mutation. 



Professor Guyer, however, goes farther, and 

 argues that, since a rabbit can also produce 

 anti-lens when injected with lens substance, 

 and since individual animals can even pro- 

 duce anti-bodies when treated with their own 

 tissues, therefore the products of the tissues 

 of an individual may permanently affect the 



factors carried by its own germ-cells. More- 

 over he asks, pointing to the well-known stim- 

 ulative action of internal secretions (hor- 

 mones and the like), if destructive bodies 

 can be produced, why not constructive bodies 

 also ? And so he would have us adopt a sort 

 of modern version of Darwin's theory of pan- 

 genesis, and a Lamarckian view of evolution- 

 ary change. 



But surely there is a wide difference be- 

 tween such a poisonous or destructive action 

 as he describes and any constructive process. 

 The latter must entail, as I tried to show 

 above, the drawing of new substances into the 

 metabolic vortex. Internal secretions are 

 themselves but characters, products (perhaps 

 of the nature of ferments) behaving as en- 

 vironmental conditions, not as self -propagating 

 fatcors, molding the responses, but not per- 

 manently altering the fundamental structure 

 and composition of the factors of inheritance. 



Moreover, the early fossil vertebrates had, 

 in fact, lenses neither larger nor smaller on 

 the average than those of the present day. 

 If destructive anti-lens had been continually 

 produced and had acted, its effect would have 

 been cumulative. A constructive substance 

 must, then, have also been continually pro- 

 duced to counteract it. Such a theory might 

 perhaps be defended; but would it bring us 

 any nearer to the solution of the problem? 



The real weakness of the theory is that it 

 does not escape from the fundamental objec- 

 tions we have already put forward as fatal to 

 Lamarckism. If an effect has been produced, 

 either the supposed constructive substance was 

 present from the first, as an ordinary internal 

 environmental condition necessary for the nor- 

 mal development of the character, or it must 

 have been introduced from without by the ap- 

 plication of a new stimulus. The same objec- 

 tion does not apply to the destructive effect. 

 No one doubts that if a factor could be de- 

 stroyed by a hot needle or picked out with 

 fine forceps the effects of the operation would 

 persist throughout subsequent generations. 



Nevertheless, these results are of the great- 

 est interest and importance, and, if corrob- 



