NOTES ON THE TOXICITY OF DILUTE SOLUTIONS 



OF CERTAIN PHENOLIC COMPOUNDS AS INDI- 



CATED BY THEIR EFFECT ON AMPHIBIAN 



EGGS AND EMBRYOS, TOGETHER WITH 



REFERENCES ON MODIFICATIONS 



OF PIGMENT DEVELOPMENT 



ROSS AIKEN GORTNER and ARTHUR M. BANTAi 



(Station for Experimental Evolution, The Carnegie Institution of Washington) 



I. INTRODUCTION 



We believe it to be a fairly well established fact that the black 

 melanic pigment results from the interaction of an oxidizing enzyme 

 of the tyrosinase type and some oxidizable chromogen, the exact 

 nature of which has never been elucidated [Gortner, 191 1 (a)]. 

 One of US [Gortner, 1911 (b)] has shown that w-di-hydroxy 

 phenols inhibit the action of tyrosinase in vitro and the Suggestion 

 was made that perhaps certain types of colorless animals owe their 

 lack of pigment to the presence of inhibitory Compounds. 



During the last two years we have been testing the effect of 

 dilute Solutions of certain organic Compounds upon pigment devel- 

 opment in amphibian larvae. A preliminary note as to the effect 

 of some of these Solutions upon pigmentation has already appeared 

 [Banta-Gortner, 1913 (a) ], but inasmuch as the place of publication 

 is not readily accessible to the chemist, a brief statement of some 

 of the results has been incorporated in this paper together with the 

 data relating to the toxicity of these Compounds. The observations 

 on toxicity were incidental to the investigations on pigmentation (to 

 be published in detail in a biological Journal) and, although frag- 

 mentary, they are perhaps of sufficient value to record. 



1 This paper represents coöperative effort, each author having as nearly as 

 possible an equal share in the work. 



357 



