BEHAVIOR OF ANURA TOWARD COLLOIDAL DYES 37 



ment extended, as in Experiment 17 g, the amount of dye stored 

 in the liver and kidneys was so great, that no estimate can be 

 definitely drawn between the amount relatively stored in each. 



Mononuclear leucocytes containing dye granules were fre- 

 quently met with in the intertubular tissue of the kidneys and 

 occasionally in the liver. They were also often abundant in the 

 mucosa of the alimentary canal. In a few instances they were 

 found in the circulation (Exp. 17 f), and in some cases, as in sec- 

 tions of the kidney, they often appeared to be overloaded with 

 dye and to be broken down (Exp. 17 f and 17 g). Mononuclears 

 which had stored the dye were observed in the circulation of the 

 pancreas (Exp. 16 b) and in the spleen (Exp. 16 b and 17 g). 



The endothelium of the venules in the spleen did not appear 

 consistently to take up the dye but in a few cases it appeared to 

 be vitally stained (Exp. 17 g). 



Without entering into further and unnecessary details, it may 

 be stated that the reactions of typical tissues toward acid dyes, 

 as far as the tissues themselves are concerned, do not appear to 

 differ in the slightest degree in these experiments from those 

 previously observed. In no instance was there any indication of 

 nuclear staining or of a diffuse staining of the cytoplasm in the 

 cells of the mucosa and submucosa in any of the individuals 

 involved. In one instance, not included on table 9, the nuclei of 

 the cells in the mucosa and submucosa, but not the cytoplasm, 

 were found to be stained in a frog that had been dead for a few 

 hours before fixation of the tissues. In this case, however, none 

 of the other tissues appeared to be pathologic in the slightest 

 degree. This frog had been fed sixteen times and died under 

 treatment on the thirteenth day. 



9. A COMPARISON OF THE REACTIONS OF THE TISSUES TOWARD 

 COLLOIDAL ACID DYES AS OBSERVED IN EXPERIMENTS CON- 

 CERNED WITH THE PORTAL OF ENTRY OF THE DYE 



On summarizing the above experiments concerning the portal 

 of entry of the dye, we find in adult frogs and toads that solutions 

 of colloidal acid dyes can gain admission to the body through the 

 skin and intestinal mucosa. A striking difference is observed in 



