No. 629] SHORTER ARTICLES AND CORRESPONDENCE 563 



Above all, it is to be regretted that in none of these experi- 

 ments have any definite pedigrees been given, nor the methods of 

 mating in the various stocks. The tables, moreover, are in most 

 cases merely summaries, the original and complete data not 

 being presented. It may well be that the full data and pedigrees 

 of all the author's extensive experiments would be too bulky for 

 publication; but in view of the fact that on this particular 

 series only is based any claim of modification or addition to 

 genetic theory, the raw data and pedigrees might profitably have 

 been included, even to the possible exclusion of a part of the 

 discussion. 



Under these circumstances, no attempt can be made at an 

 analysis by ordinary genetic conceptions. This whole experiment 

 illustrates perfectly the real basis of the familiar distinction 

 (implied also by the author in this volume) between results ob- 

 tained "in the laboratory" and "in nature." The real differ- 

 ence, as well shown in this case, is merely one between working 

 with known materials under controlled conditions and uncon- 

 trolled operations with unknown things. 



■ This particular experiment has been irvicwcil at Inmth. be- 

 cause it is, apparently, solely upon it tliat the author bases a 

 large amount of rather far-fetched sfxMMilaiion on the "arelii- 



sci'VPil fosults aft' (111.'. inniifili;itt>ly. to a ( rcvorsible') change in 

 the >7 /r///o//.s- (}f th< </(H(tic lactors In nich oflnr: (2) that these 

 chati^-i>s ar(^ the d[r>ct r( .<iilf of the cn>.s.-<is: (•'! i lliat these partic- 



direct effect of (cumulative) environmental influence on the rate 

 of ontogeny; and (4) that the results are profoundly and perma- 

 nently modified by the environmental conditions surrounding 



