LEE BARKER WALTON 137 



on the origin, but merely on the redistribution of the 

 character-forming units already present in the stock 

 utilized. Another explanation not taking into account 

 the purity or impurity of the parental stock, accounted 

 for "mutations" through the sudden ineffectiveness or loss 

 of a gene. 



The dissatisfaction thus arising resulted in the return 

 of many to the fold of "acquired characters." Semon 

 (1912) reviving the "mneme" principle received the sup- 

 port of Wettstein, Przibram, and others. A disinclina- 

 tion existed, however, among most naturalists to accept 

 the evidence presented as seriously upholding the inheri- 

 tance of new characters produced by environmental 

 stimuli. Explanations of the results on quite other grounds 

 seemed more plausible. For example, the work of Tower 

 (1906), (1910), etc., in attempting to control the color 

 pattern of the potato beetle by changes in temperature 

 and humidity, encountered the impurity of the germplasm 

 objection as well as the gene loss objection, either one of 

 which would be fatal to the validity of the conclusions, if 

 sustained. Commenced at a period in 1895, prior to the 

 rediscovery of the principles dealing with alternative in- 

 heritance, and finished in 1904 before the facts were duly 

 appreciated, it is not at all improbable that genetic com- 

 plications in the way of recessives, modifiers, losses, lethals, 

 etc., were involved. The destructive criticism presented 

 by Cockerell, Gortner, Bateson, Castle, and others, partic- 

 ularly in reference to the later studies of Tower (1910), 

 makes it evident that the results must be confirmed from 

 independent sources with more consideration to the pos- 

 sible errors mentioned before the conclusions are to be 

 accepted. 



Similarly, the work of MacDougal (1907), in connec- 

 tion with the modification of Raimannia odorata, one of 

 the Patagonian primroses, may be explained. Compton, 

 as noted by Bateson (1912), using the same species, was 

 unable to obtain like results, while Humbert (1911) 

 utilizing 7,500 pure line plants of Silene nocti flora, one of 

 the "pinks" also failed to obtain so-called "mutants" simi- 

 lar to those found by MacDougal. 



