1914] Ross Aiken Gortner and Arthur M. Banta 359 



noting the increased toxicity of the sol, due to the action of light, are 

 the eggs and embryos of Spelerpes bilineatus. This Salamander egg 

 is without pigment, so that the early development of pigment in the 

 embryo can be easily followed. A total of about 150 experiments 

 were run on this material using conc. of 0.0125-0.025 percent. We 

 obtained in every instance a retardation of growth, accompanied by 

 a much greater retardation in pigment development, than would cor- 

 respond to the retardation in growth. In some of the experiments, 

 where the conc. of orcinol was low and the time of immersion was 

 short, we did not obtain permanent af ter-effects and the later course 

 of development resembled that of the control. When, however, the 

 strength of the orcinol was high (0.02-0.025 percent) and the treat- 

 ment sufficiently prolonged, varying from i day to a week or more 

 depending on the initial age of the embryo, we have apparently ob- 

 tained permanent modifications. The nature of these effects de- 

 pends somewhat on the initial age of the egg or embryo. When 

 eggs at a stage of development between the early blastula and the 

 late neural groove are kept in the sol. less than 6 days, they rarely 

 show types as abnormal as those which have been exposed to the 

 action of the drug for from 6 to 20 days. They do show, however, 

 the typical retardation of pigment development and various other 

 characteristics sufficient to classify them as "modified." 



When these early embryos are kept in the sol. for more than 

 6 days, the course of development is much different. The larva de- 

 velops in many cases normally, although somewhat slowly, until 

 within a short time before hatching when huge swellings appear, 

 sometimes filling the entire body with great serous cavities through 

 the walls of which may be seen the alimentary canal and the blood 

 vessels, stretched almost to breaking. In this condition they may 

 live for some days but eventually die without further development. 



If, however, the embryos are older when first treated, i. e., with 

 the head strongly differentiated or at any later stage up to the 

 beginning of pigmentation (which occurs shortly before hatching), 

 the effect is widely different. In no instance do we obtain the blis- 

 tered larvae but instead short, heavy individuals, about one third 

 shorter and twice as broad as the controls. These we class as the 

 true "orcinol type." They are distinguished from the controls by 



