338 PROCEEDINGS OP THE AMERICAN ACADEMY. 



Perhaps the ablest objector to this phase of Weismann's theory of 

 heredity is Kolliker,* who (1) denies that tliere is any fundamental 

 difference between body and germ plasm ; and (2) claims that in the 

 various cellular changes the characters of the original germ plasm may 

 be either wholly retained, or degenerate, or be wholly lost. 



Sir William Turner f and other medical men also favor the theory 

 of the transmission of acquired characters. He suggests that the more 

 subtle processes of generation may be transmitted where mutilations 

 may not. 



Detmer J likewise opposes Weismann's view on the following 

 grounds : — 



1. The intimate histological influences of external conditions on 

 the organism. 



2. The importance of correlation in allowing an influence to satu- 

 rate from one part to another, and thus to the sexual cells. 



3. The suggestiveness of the persistence of certain phenomena (in 

 plants) after the inciting conditions have ceased. 



The criticisms of Kolliker have been ably discussed by Weismann 

 in his Essays upon Heredity. 



The views which have had weight with us, and which seem to oppose 

 Weismann's theory that acquired traits cannot be transmitted, are the 

 following : — 



1. The laws of correlation («) of growth, and (b) of organs in the 

 mature organism. 



If one part or organ of the body is removed, aborted, or changed, 

 the rest may, in certain cases, be either temporarily or permanently 

 affected by the change. 



2. Whatever affects the body in general would tend to affect the 

 germ plasm, since the tissues and cells of the ovaries and testes are 

 supplied with blood, and are innervated like other parts and organs 

 of the body ; hence the plasm of the nuclei of these cells, though 

 it may exist in a temporarily indifferent state is nourished, or at least 

 preserved from degeneration, and is thus influenced by whatever affects 

 the body. 



3. The operation of castration in either sex, as is well known, re- 



* Das Karyoplasma unci die Vererbung. Zeitschrift fiir wissens. Zoologie, 

 XL. iv. 228, 1886, and Anat. Anzeiger, III., 1888. 



f Report of the British Association for the Advancement of Science for 

 1889, pp. 756-771. 1890. 



t Zum Problem der Vererbung. Archiv fiir die ges. Physiologie, XL. 

 1887. 



