ARTICLES 405 



determine whether the altered condition is transmitted to the 

 offspring. Meanwhile, new and startling evidence of the 

 inheritability of acquired changes has come in from a totally new 

 quarter. 



Two American observers (Messrs. Guyer and Smith) have 

 published in the Journal of Experimental Zoology (vol. iii, 1920) 

 an account of their experiments on rabbits. They took the 

 lenses of the eyes of rabbits, pulped them in Ringer's solution, 

 and injected small portions of the resulting fluid into domestic 

 fowls. After the lapse of a few weeks the serum of the fowl's 

 blood developed an " antibody," which tended to dissolve 

 and disintegrate the lens of the rabbit. Small quantities of this 

 serum were then injected into pregnant rabbits. The mothers 

 were unaffected, but some of the young which they bore showed 

 on one or both sides of the head diminished or completely aborted 

 lenses and correspondingly developed retinae, for, as we have 

 already seen, the development of one of these elements of the 

 eyeball depends on that of the other. Many of these young 

 with imperfect eyes died, but some survived, and these mated 

 together, gave rise to young some of which showed the defect, 

 and this defect was observable through six generations, without 

 any further injection of serum. Two instances also of inheritance 

 through the male alone were noted — that is to say, that an 

 affected male mated with a normal doe gave rise to young 

 some of which showed the defect. 



Messrs. Guyer and Smith say : " It is a noteworthy fact that 

 once the defects were established, without any subsequent treat- 

 ment, they became more and more pronounced in successive 

 generations." The authors suggest that " the degenerating 

 eyes are themselves directly or indirectly originating antibodies 

 in the blood-serum of their bearers — which in turn affect the 

 germ- cells. ^^ 



If this conclusion be accepted, the cardinal principle of the 

 theory of the inheritability of acquired characters, viz. the 

 influence of the soma on the germ, is conceded. 



We conclude, then, by saying that a very strong prima facie 

 case for the inheritability of acquired characters has been made 

 out, and that no serious efforts have yet been made to combat 

 the evidence. We are entitled to use the principle of use- 

 inheritance in endeavouring to explain the facts of Palaeon- 

 tology and Embryology, and when we do so, we find a flood of 

 brilliant light thrown on these subjects, and a whole variety of 

 puzzling phenomena become susceptible of rational explanation. 



