OBSERVATIONS AND EXPERIMENTS 221 



black and yellow pigment cells at the base of the dor- 

 sal fin and on the lower side, and two longitudinal 

 stripes extending as far as the head. The normal fish 

 did not present any pigmentation on the lower side of 

 the body. 



This experiment appears conclusive. In this case 

 one cannot speak of a general condition, nor of trans- 

 mission of a chemical substance, nor even of a simul- 

 taneous action on the germ and soma cells. How 

 could the germ cells be affected by the absence of 

 light? A character incontestably acquired and ex- 

 clusively somatic has consequently been transmitted 

 hereditarily. And yet we must state, not because the 

 arguments presented have any value, but in order to 

 show how far prejudice may go, that the Anti-La- 

 marckians find reasons for rejecting this evidence. 

 Th. H. Morgan addresses to Cunningham the follow- 

 ing criticism: "It is not shown that if the loss of 

 colour on the lower side had been the result of the in- 

 heritance of an acquired character, the results seen 

 in Cunningham's experiment would follow as a con- 

 sequence." 6 To give some weight to his criticism 

 Morgan should tell us how things should have turned 

 out in this case. Since he failed to do so, we can but 

 accept Cunningham's conclusion, for no other inter- 

 pretation of his observations seems plausible. Mor- 

 gan also offers another explanation of the phenomena 



• Evolution and Adaptation, p. 258. 



