10 



CHARLES F. W. McCLTJRE 



TABLE 3 

 B.ufo lentiginosus 



allowed to develop in a dark room and were never exposed to the 

 light. The concentration of the dye solution (1:1000 trypan 

 blue), the date of immersion (June 4) and the age of the larvae at 

 the time of immersion were the same in both cases. 



Thirty-one (31) larvae were involved in this experiment. 

 Certain of these larvae were transferred daily from the dye solu- 

 tion to tap water, from June 7 to June 11, inclusive, in which they 

 remained twenty-four hours before killing and fixation. 



An examination of serial sections of eleven (11) larvae killed 

 on June 8 showed that no dye had been stored in the cytoplasm 

 of the cell in any tissue of the body. 



' In seven (7) larvae killed on June 9 (ninth day after fertiliza- 

 tion), nine (9) killed on June 10, two (2) killed on June 11 and 

 two (2) killed on June 12, dye granules were invariably found in 

 the cytoplasm of the cell in certain typical tissues. No apparent 

 difference was observed in the behavior of larvae which were 

 allowed to develop in a dark or light room, as far as reactions 

 toward dye are concerned. 



If we summarize the above experiments, we find among the 140 

 larvae of Bufo placed on the third and fourth days after fertiliza- 

 tion in solutions of colloidal acid dyes, that dye was stored in the 

 tissues of only three of the 66 larvae killed at successive intervals 

 previous to the ninth day. Also, that in all except 2 of the 31 

 larvae killed on the ninth day after fertilization, and in all of the 

 43 killed at successive intervals subsequent to this time, dye 

 granules were invariably present in the cytoplasm of the cell in 

 certain typical tissues. 



