164 Heredity and Eugciiies 



inteqirctatirtn and arc not elucidations of the problems. 

 The main reason why this is so is that the materials that 

 have been used and the methods of exj)erimentation have 

 not been properly guarded. Thus, for example, the recent 

 results of Kammerer with various amphibians and Lacerta., 

 Woltereck's investigations upon Dapliiiia, Zederbauer's 

 experiments with Bursa, Sumner's with mice, as well as all 

 of the older experiments, admit of "interpretation" from 

 either point of view. Thus Semon " interj^rets " all of these 

 and man}- more besides as shoA\'ing the strength of the neo- 

 Lamarckian position at the present time. A neo-Darwinian 

 could make an equally good case of the same data. 

 At present the conclusi\'e evidence from Castle's trans- 

 plantation of ovaries in guinea-pigs, Davenport's negative 

 results with poultry, and experiments like those with color 

 in Lcptinotarsa have all given exactly the expected result 

 without c|ualifications. MacDougal, in discussing some of 

 these problems, says: "The time has now arrived when the 

 claimants for neo-Lamarckianism and all of its conclusions 

 must show cause for its further consideration, or else allow 

 it to drop from the j^osition of being seriously taken as a 

 method of evolutionary advance." 



With this most biologists will at present agree, but 

 unfortunately, from time to time, some careless experi- 

 menter with more partisan enthusiasm than judgment or 

 experimental acumen will come forward with conclusions 

 derived from experiments wherein the most elementary 

 essentials of genetic research are ignored and reassert the 

 transmission of somatic changes. Present experimental 

 e\idence, where critical, clearly indicates the increasing 

 doubtfulness of the validity of the hypothesis of somatic 

 transmission. 



