Jons. Schmidt !;'):{ 



at rt consUiiit U'mjH?nittire and with regular vcntilati<»t). The* conditionH 

 with R'gjinl U> tmifonuity won* in my opjuinn (h«* inoHt rjivonnihlr 

 ptkssiblo and I cannot but conclude from the priHcnt ex|)crinient, thai 

 the difference pt-oved to erutt in the offspring of parents with resj)€ctivel y 

 6 and 8 my* is of hereditary (genoty/ncal) nature. 



IV. Concluding Remarks. 



The investigations here treated fall into two groups: (1) KxjM'ri- 

 ments in which the same mother was exposed to different environments 

 in dirterent jn-riods of pregnancy and (2) Experiments in which different 

 mothers weiv exposed to the stntie environment, have thus succeeded in 

 ehicidating thesi' n\tht»r compliaited (piestions. 



It has been shown that tht' number of organs may be very susceptible 

 to environment, but that this fact cannot — under suitable experimental 

 conditions — disguise the fact, which we specially wanted to demonstrate, 

 viz. that there are or may bi' differences of hereditary nature between 

 the various individuals. 



This proof is of considerable interest for our view upon the nature 

 of " races " in fishes, and supports in a high degree the opinion expressed 

 by me at a previous occasion': "My view then, with regard to the 

 nature of ' races ' in fishes, as characterised by our population analyses, 

 is briefly this : A fish ' race ' is largely a statistical conception. It 

 implies a mixing of different genotypes, and the average values 

 characterising the ' race ' are primarily dependent upon the (luantita- 

 tive proportion between these ; only secondarily on the environment." 



' Jobs. Schmidt, "Racial Studies in Fishes. I. Statistical Investigations with Zoarce« 

 viviparugy L.," Journal of Genetics, Vol. vii. p. 117, 1918. 



