Original Method of Artificial Parthenogenesis 171 



into Delage's mixture which is merely a hypertonic solution 

 rendered alkaline by an excess of NH4OH. It is obvious that 

 in this case the solution of Delage could have produced only 

 the corrective effect tjrpical for hypertonic solutions. The addi- 

 tional NH4OH could do no good, and probably did some harm. 

 The larvae which were produced by this method did not de- 

 velop as far as those produced when the simple hypertonic sea- 

 water, as I use it, was added. 



Delage has drawn the conclusion that in his experiments 

 the tannic acid causes a coagulation and the alkali a liquefac- 

 tion, and that development is due to an alteration of coagula- 

 tions and liquefactions. Since we have shown in this and the 

 previous chapter that the mere treatment of the eggs with an 

 alkaline hypertonic solution causes the production of parthe- 

 nogenetic plutei, and since it can be demonstrated that any 

 hypertonic solution containing the proper amount of NH4OH 

 or any other weak base acts as well as Delage's solution, the 

 conclusion he draws from his observation becomes untenable. 



