ORIGIN OF MONSTERS 565 



in the dishes into which acetone-treated eggs had been trans- 

 ferred the sediment made the impression of a granular precipi- 

 tate. Chemical analysis of these sediments may eventually dis- 

 close the nature of the chemical alteration of the eggs treated 

 with these organic acids. 



One rather evident effect which they have on the egg is that 

 they increase its permeabilitj^ For on transfer from the solu- 

 tion to pure sea-water the eggs, owing to increased imbibition 

 of sea-water, swell to an unusual size; after some time, however, 

 they return to approximately the normal size and occasionall}^ 

 some eggs may be found considerably below the size of the 

 normal, untreated egg. This indicates that the increase in per- 

 meability has called forth an increase in endosmotic pressure 

 (imbibition) which allowed enough sea-water to enter the egg 

 to dilute the substances dissolved by the acids, and a subsequent 

 increase in (ex) osmotic pressure (shrinkage) owing to which the 

 dissolved substances have passed out of the eggs and formed 

 the sediment on the bottom. 



Besides these two factors (toxicity of the medium and osmotic 

 pressure) which are directly concerned with blastolysis there 

 seem to be some other factors, to which apparently is due the 

 enormous variation in the blastolytic effect and consequently 

 the variation in the morphological deviations from the typical 

 development. While some observations have been made which 

 may bear on the nature of these factors, I can make no definite 

 suggestion at this time and the determination of these factors 

 must be deferred to future experiments. 



However, while the analysis of blastolytic action into its com- 

 ponent factors must thus for the present time remain incom- 

 plete, the evidence of this action is indeed very striking in 

 practically all deformed embryos of my experiments. 



Considering the fact that all these terata have been produced 

 by experimentally induced blastolysis from eggs which would 

 in a normal environment have given rise to normal embryos, it 

 would no longer seem to be necessary to assume 'germinal varia- 

 tion' as the cause underlying the origin of ophthalmic monsters 

 and various duphcate twins, as this has been postulated by 



