2,627 oxicity of Dilute Solutions of Phenolic CompoundslApr{\-]uly. 



extreme edema noted in the Spelerpes larvae. It is not unusual to 

 observe serous cavities almost large enough to hold the entire body 

 of a normal larva. The normal increase in size of the embryo is, to 

 a large extent, brought about by the imbibition of water, and itwould 

 seem that dilute sol. of orcinol or resorcinol may so influence this 

 process as to destroy the delicate balance of the mechanism which 

 regulates the amount of water absorbed ; as a result the water flows 

 through the epidermis until the tension produced by the tightly 

 stretched body wall prevents any further osmosis. If these phenols 

 in such small conc. can produce such a result, it seems possible that 

 edemic conditions may be traced, in other instances, to a similar ac- 

 tion by minute traces of poisonous metabolic products retained 

 within the tissues. 



Experiments with /j-di-hydroxy benzene (Hydroquinone). 

 Developing eggs and embryos of Spelerpes hilineatus, Rana sylvat- 

 ica, Hyla pickeringii and Amhly Stoma punctatum, when placed in 

 sol. of hydroquinone of 0.25-0.005 percent conc, were dead in 

 every instance within 24 hr. The dilution was not carried lower 

 than 0.005 percent. 



Experiments with o-di-hydroxy benzene (Pyrocatechin). 



Developing eggs of the amphibia noted above were placed in sol. 



of pyrocatechin of 0.5-0.005 percent conc. All the frog eggs were 



dead within 24 hr. ; the jell was darkened, varying f rom deep smoky 



to black depending on the conc. of the pyrocatechin. The eggs of 



Spelerpes were also all dead within 24 hr. in all dilutions, the colorless 



tgg having become brownish in color and the tgg membranes a 



bluish black. The eggs of Amblystoma were apparently muchmore 



hardy; those in conc. of 0.05 percent or greater died within a few 



hours, but in 0.01-0.005 percent conc, they continued to live for 



several days, although their development was very greatly retarded 



and never passed the blastopore stage. The membranes in all cases 



assumed a deep smoky color.^ 



2 In collaboration with Dr. Goodale one of us (G.) injected hen eggs with 

 various chemicals to determine effects upon the course of development. One of 

 these chemicals was pyrocatechin — about i c.c. of i per cent. sol. to each egg. In 

 every case the eggs were found soon to show an intense opacity when candled and, 

 upon opening them, the contents were found to be almost as black as ink. This 

 is probably the result of an oxidation, possibly induced by an oxidizing enzyme, 

 but tyrosinase is absent f rom the hen egg, or at least gives no corresponding color 



