564 E. I. WERBEE 



various combinations. The difficulties of such investigations 

 are numerous, even if the most important one did not exist, 

 namely that the experimental pathology of metabolism is prac- 

 tically yet in its infancy. But such difficulties may perhaps in 

 time be at least partially overcome. And while the complete 

 solution of the problem of the causal factors underlying the origin 

 of monsters may yet be distant, well planned experiments and 

 careful analysis of results may at least furnish direct evidence 

 for the correctness of our assumption that monstrous develop- 

 ment is primarly due to parental metabolic toxaemia, an hy- 

 pothesis which in view of the noted results of our experiments 

 would seem to be well justified. 



Om- experiments have, besides, pointed out the direction for 

 investigations into the morphogenesis of monsters. In the pre- 

 ceding pages I have shown that microscopic analysis of all 

 monsters discloses evidence of an action on the egg treated with 

 butyric acid and acetone, which tends to dissociate (or disrupt) 

 the germ's substance. This action, blastolysis, is a complex com- 

 ponent in the sense of Roux ('95), being the result of the col- 

 lective action of a number of factors potent in a varying degree 

 in all eggs. 



Some observations made in experiments during the summer 

 of 1915 seem to suggest that the most important direct factors 

 whose action results in blastolysis are the toxic effect of the 

 chemical modification of the environment and an increase in 

 osmotic pressure mainly after transfer of the eggs to pure sea- 

 water. The first materially alters or destroys parts of the germ, 

 while the latter may be regarded as a very forceful dissociating 

 agent which disrupts the injured germ. The alteration brought 

 about by the action of butyric acid or acetone seems to be due 

 to the solvent action of these acids. To these conclusions would 

 seem to point the fact that some hours after transfer of the eggs 

 from butyric acid or acetone into pure sea-water there could in- 

 variably be found a sediment at the bottom of the dish in which 

 they were kept. 



The sediment was of a slimy consistency in the dishes con- 

 taining eggs which had been treated with butyi'ic acid, while 



