ORIGIN OF MONSTERS 487 



impossible. This is, essentially, a chemical theoiy of terato- 

 genesis for it assumes the atj'pical development of the embryo 

 to be due to lack of necessary substances. 



More direct support for the chemical theory of teratogeny is 

 offered by the recent investigations of Stockard ('07, '09, '10 a) 

 and McClendon ('12 a and b), both of whom obtained one-eyed 

 monsters by subjecting developing teleost eggs to the action of 

 various toxic substances, such as magnesium chloride, alcohol, 

 ether, alkaloids, etc. These investigations have shown that some 

 such developmental deviations as are found to occur spontane- 

 ously may be brought about by the chemical action of various 

 substances, and thus they suggest that atypical development in 

 nature may be due to pathochemical alterations of the germ's 

 environment. • 



The above considerations have led me to assume that in order 

 to attack the problem of atypical development in nature effec- 

 tively it is necessary to find the unusual chemical factors which 

 cause the embryo in its natural environment to develop in a 

 defective or monstrous manner. 



Since the metabolism is the greatest source of chemical modifi- 

 cations of the body, I concluded that the solution of the problem 

 of the causal genesis of monsters must be sought for in pathologic 

 parental metabolism. 



Starting from this assumption, I carried out, in the summer 

 of 1914, some experiments on Fundulus heteroclitus, the ferti- 

 lized eggs of which were subjected to the action of solutions of 

 urea, butyric acid, lactic acid, acetone, sodium glycocholate and 

 ammonium hydroxide. Conclusive results were so far obtained 

 only with butyric acid and acetone. The (rather simple) methods 

 employed have been described in a former paper (Werber '15 c) 

 to which the reader is referred. 



II. THE RECORDED TERATA 



The results which were obtained are very much aUke in both 

 series of experiments, with butryic acid and acetone. The 

 variety of deformities being almost endless in both, it would be 

 practically impossible to present much more than certain types 



