ORGANIZATION AND GROWTH 239 



of the entire animal or the individual organs is decreased. 

 The result is therefore similar to that obtained in the pre- 

 vious experiments; wherefore I believe that the influence of 

 concentration upon the conversion of the genera Artemia 

 into Branchipus is to a large extent nothing but an expression 

 of the dependence of animal growth upon the absorption of 

 water. Schmankewitsch also mentions that in the same 

 length of time the animals in the dilute salt solution 

 (Branchipus) grow more rapidly than those in the concen- 

 trated salt solution (Artemia): "At the same temperature, 

 the growth of specimens of Artemia salina in highly concen- 

 trated sea water is less than a third as great as the growth 

 of Branchipus ferox in the less concentrated sea water." But 

 that we are, indeed, justified in this case in substituting for 

 the conceptions of "adaptation" and "change of species" 

 toward which Schmankewitsch takes a more critical view 

 than most Darwinians the osmotic dependence of longitu- 

 dinal growth upon the concentration of the salt solution, is 

 well shown by a fact, which is especially emphasized by 

 Schmankewitsch, that the "change" persists in the suc- 

 ceeding generations only as long as the animals remain in 

 the sea- water of the altered concentration as should be the 

 case if we are dealing merely with osmotic effects during the 

 period of growth. Since not only the absorption of water, 

 but also the secretion of water, must be considered in such 

 experiments as have been detailed here, it is to be expected 

 that the growth of all animals and all organs is not affected 

 to the same extent by changes in the concentration of the 

 salt solution. 



4! Schmankewitsch interprets the effect of the concentra- 

 tion of the salt solution upon changes in the characteristics 

 of the animals in a different way ; he attributes it solely to 

 the fact that with the increase in the concentration the 

 amount of air dissolved in the salt solution is decreased, and 



