568 E. I. WERBER 



products of pathologic metabolism should have an injurious 

 influence on the male sex-cells — and there is every reason to 

 believe that they do have such an effect — the chance for a terato- 

 genic influence of parental metaboUc toxaemia on the offspring 

 is greatly enhanced. 



Elsewhere I (Werber '15 b) have pointed out the bearing 

 which these conclusions and the results of my experiments with 

 products of metabolic toxaemia on the teleost ovum may have 

 on some, so far elusive, problems of medicine. Not less evident 

 is their possible significance for eugenics and the biology of the 

 race. 



From the point of view, however, of the embryologist and 

 pathologist our hypothesis and the results of the present experi- 

 mental study based on it would seem to offer a rational basis 

 for the solution of the old problems of the etiology and the 

 morphogenesis of terata occurring spontaneously in many ani- 

 mals and notably in man and other mammals. 



These problems may, I think, now be, at least partly accessi- 

 ble to experimental control. 



V. SUMMARY 



1. Recent results of investigations in experimental eitibryology 

 and teratology pointed to the conclusion that the primary causes 

 underlying the origin of monsters in man and other mammals 

 are of a chemical nature. They also suggested that in the 

 latter, particularly, these striking deviations from the develop- 

 mental norm are due to autogenous chemical modification of 

 the parental blood during disturbances of metabohsm. 



2. On the basis of this hypothesis experiments were performed 

 on fertiUzed eggs of Fundulus heteroclitus which were subjected 

 to the action of some substances of certain metabolic toxaemias, 



3. Positive results were obtained with particularly two sub- 

 stances, which occur in toxaemia due to disturbances of carbo- 

 hydrate metabolism, namely butyric acid and acetone. 



4. A very great variety of monsters has resulted from these 

 experiments, analogous to human and other mammalian mon- 

 sters. The deformities concern the eyes (cyclopia, synophthal- 



