PRESENT CRISIS IN EVOLUTIONARY THOUGHT 15 



cially when, as is always the case in these experiments, the 

 modification produced is destructive rather than constructive. 

 The experiments, therefore, of Prof. M. F. Guyer of Wisconsin 

 University, in which a germinally-transmitted eye defect was 

 produced by injecting pregnant female rabbits with an anti- 

 lens serum derived from fowls immunized to the crystalline 

 lens of rabbits as antigen, are beside the mark. To demon- 

 strate the Lamarckian thesis one must furnish evidence of a 

 constructive addition to inheritance by means of prior somatic 

 acquisition. The transmission of defects artificially pro- 

 duced is not so much a process of inheritance (transmission of 

 type) as rather one of degeneracy (failure to equate the 

 parental type).^ Commenting on Guyer's suggestion that an 

 organism capable of producing antibodies that are germinally- 

 destructive, may also be able to produce constructive bodies, 

 Prof. Edwin S. Goodrich says: "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 normal development 

 of the character, or it must have been introduced from without 

 by the application of a new stimulus. The same objection 

 does not apply to the destructive effect. No one doubts that 

 if a factor could be destroyed by a hot needle or picked out 

 with a fine forceps the effect of the operation would persist 

 throughout subsequent generations." {Science, Dec. 2, 1921, 

 p. 535.) 



But in demonstrating against the Neo-Lamarckians that 

 somatic modifications unrepresented in the germ plasm could 

 have no significance in the process of racial evolution, Weis- 

 mann had (proved too much. His argument was no less telling 



* A good definition of degeneracy is that of A. F. Tredgold, who says: 

 "I venture to define degeneracy as 'a retrograde condition of the indi- 

 vidual resulting from a pathological variation of the germ cell.' " 

 (Smithson. Inst. Rpt. for 1918, p. 548.) 



