40 CHARLES F. W. McCLURE 



10. ON THE REACTIONS OF THE TISSUES TOWARD COLLOIDAL ACID 

 DYES DURING THE SEASON OF HIBERNATION 



All of the experiments above-mentioned were conducted during 

 the Spring and Summer months. It is therefore of interest to 

 compare the reactions of the tissues toward colloidal acid dyes 

 during what would ordinarily be the period of hibernation. 



Large tadpoles of R. catesbiana obtained early in October and 

 adult toads obtained in September were kept in the laboratory at 

 ordinary room temperature up to the time the experiments were 

 made. As the animals were kept in a fairly warm room and were 

 more or less active during the Fall and Winter they have not, 

 strictly speaking, been in a hibernating state. It may prove of 

 interest, however, to compare the results of these experiments 

 with those made during the Spring and Summer. 



Experiment 18 (compare with table 8, p. 32). An adult toad 

 was allowed to remain in a finger bowl containing a freshly-made 

 1 :100 solution of Niagara blue for several hours daily, from 

 December 7 to December 13, inclusive, and killed on December 

 14. The actual length of time the toad remained in dye during a 

 period of seven days was thirteen hours and forty-five minutes. 



The walls of the intestinal canal were slightly stained but the 

 muscles of the body retained their natural color. A mass of dye 

 was found in the rectum. The large abdominal lymph sacs were 

 filled with an unusual amount of clear lymph which gave the body 

 an oedematous appearance. Sections were made of the liver and 

 kidneys. 



A mere trace of dye was occasionally stored in some of the 

 stellate cells of the liver capillaries. Not a trace of dye was 

 found in the epithelium of the tubules in the kidneys. No 

 mononuclears containing dye granules were observed in the inter- 

 tubular tissue of the kidneys. 



Experiment 19 (compare with Experiment 8, p. 22). a) A large 

 tadpole of R. catesbiana with hindlegs was placed in a 1 : 1500 

 solution of trypan blue on November 20 and allowed to remain in 

 the same until November 24, when it was killed (4 days in dye). 



The merest trace of dye was found in a few of the stellate cells 

 of the liver. Not a trace of dye was observed in the epithelium of 



