OF ENVIRONMENT 121 



egg or sperm, in such manner that these effects 

 would be transmitted to succeeding generations. 



The most obvious and the most primal relation 

 between the soma and the egg is the nutritive one, 

 and a review of the evidence offered by Pictet 

 and others leads to the conclusion that the char- 

 acter of the building material supphed to the egg 

 as varied by environmental influences may work 

 changes that pass from one generation to an- 

 other, so that it is indubitably estabhshed that the 

 egg is not isolated and possessed of such highly 

 developed selective power that it may avoid the 

 intrusion of unusual substances. 



The experiments of Oscar Riddle, S. H. and 

 S. P. Gage,^ in which it was shown that Sudan 

 III, a dye, fed to a hen, results in the coloration 

 of the yolk of her eggs, and that the chicks 

 hatched from such eggs take up the dye from the 

 yolk, which finds a lodgment in their own fatty 

 tissues, are of special interest in this connection. 



Actual available evidence does not warrant us 

 in predicating any other form of influence of in- 

 ternal region upon the germ-plasm as it takes 

 form and special activity in the egg and sperm, 

 beyond that of physio-chemical processes orig- 

 inating in the soma. Alterations in these proc- 

 esses which might affect the egg and be registered 

 in its hereditary activities might occur at any 

 stage of the ontogeny without direct reference to 

 the time intervening between the reception of the 



^ Science, 2S: i9i. 1908. 



