BEHAVIOR OF ANURA TOWARD COLLOIDAL DYES 27 



blue and the larva killed in the morning of May 13. A study of 

 serial sections showed that no dye had been stored either in the 

 cytoplasm of the stellate cells of the liver or in the epithelium of the 

 tubules in the pro- and mesonephros. Certain of the tubules in 

 both kidneys, however, presented a bluish appearance which 

 indicated that dye had reached the circulation. 



c) The tail of a larva of R. sylvatica was suspended for about 

 twenty minutes daily on three consecutive days (May 11, 12 and 

 13) in a 1 : 1000 solution of trypan blue and the larva killed in the 

 morning of May 14. Serial sections showed the unmistakable 

 presence of dye granules in the cytoplasm of the stellate cells of 

 the liver and in the epithelium of a number of tubules in the pro- 

 and mesonephros. The above-mentioned larvae were about 

 thirty-three days old on May 11 and may be regarded as fairly 

 advanced larvae. 



Experiment 11. (Partial immersion of larvae in solutions of 

 high concentration). 



The caudal fourth of the tails of two larvae of R. pipiens (34 

 days after fertilization) were suspended in a 1 : 100 solution of 

 trypan blue for one-half hour in the morning and afternoon of May 

 3, and the larvae then transferred to tap water. Both larvae were 

 killed in the morning of May 4, after remaining about twenty- 

 four hours in tap water. The portion of the tail which had been 

 submerged in dye sloughed off during the night, but at time of 

 killing the wound had healed and both tadpoles were very active. 

 Before the larvae had been suspended hi the dye the heart beat 

 was about one hundred and fourteen to the minute. After one- 

 half hour suspension in dye the heart beat was reduced to ninety. 



An examination of serial sections of both larvae showed that 

 dye granules had been deposited in abundance in the stellate 

 cells of the liver and in the epithelium of the pro- and mesonephros. 

 Dye granules were also found in the endothelium of some of the 

 lymphatics, but were not observed in that of the large ventral 

 cephalic lymph sinus. 



This experiment, when compared with Experiments 6 and 7, is 

 especially interesting by showing the rapidity with which typical 

 tissues may react toward acid dyes, when advanced larvae are 



