24 



E. J. LUND 



protein grains. This, therefore, shows that the chemical nature 

 of the substance in the vacuole may, and does in this case, deter- 

 mine whether it shall be extruded or not. Table 6 (b) shows 

 the effect of the adsorbed dye upon the process of digestion of 

 vitellin. The stain retards and sometimes even prevents digestive 

 action. This was seen from the fact that the corners and edges 

 of the grains where little or no unstained yolk exists, persist 

 more markedly than those of the unstained grains. The stained 

 grains, nevertheless, often became smaller by shrinkage, caused 

 apparently by solution of the protein from the deeper parts of 

 the vitellin grain, which may have been stained less deeply. 

 That the adsorbed dye interferes, to some extent, with the 

 maintenance of the normal form and outline of the animal is 

 shown by the results of table 6 (c) . The fact that, for example, the 

 total number of normal individuals of those fed a stained grain 

 has increased rather than decreased at the eleven-hour record, 

 since the nine-hour record was taken, is due to regulation of form, 

 either by closing and opening the oral pouch, or by undergoing 



TABLE 6 



Showing the results of feeding one grain of vitellin stained in congo red, to each of a 

 set of forty individuals. For comparison (control) another set of forty individuals 

 were each fed 1 grain of unstained vitellin 



(a) Total number of individ-1 



uals that had extruded \ 

 grains before death J 



(b) Total number of individ-1 



uals that had completed \ 

 digestion of grains J 



(c) Total number of individ- 



uals that were normal in 

 form 



(d) Total number of individ- 



uals dead 



(e) Total number of individ- 



uals with a perceptible 

 amount of liquid in 

 vacuole 



Stained.... 

 Unstained 



Stained . . . 

 Unstained 



Stained . . . 

 Unstained 



Stained . . . 

 Unstained 



Stained . . . 

 Unstained 



TIME IN HOUBS AFTER FEEDING 





 





 



38 

 37 





 





 





 





 



35 



38 





 







4 



1 4 







01 

 1 4 



27' 26 



37 





 







7 



38 





 





 13 



11 13 22 



91 18 







0; 



id 22 



15 24 



34 33 



0, 3 4 

 .0 



27 

 





 37 



14 

 29 



11 

 2 





 2 



