ORIGINAL METHOD OF ARTIFICIAL PARTHENOGENESIS 171 



into Delage's mixture which is merely a hypertonic solution 

 rendered alkaline by an excess of NH 4 OH. It is obvious that 

 in this case the solution of Delage could have produced only 

 the corrective effect typical for hypertonic solutions. The addi- 

 tional NH 4 OH 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 NH 4 OH 

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

 conclusion he draws from his observation becomes untenable. 



