130 



CYTOPLASMIC INCLUSIONS 



and Grasse, 1933); in Ichthyophthirius (MacLennan, 1936), the diges- 

 tive granules (Fig. 31) enter the gastriole, but the mitochondria are 

 never associated in any visible manner with the digestive mass. A more 

 detailed description of digestion will not be given in this section, since 

 attention is here centered on the granules. 



All careful descriptions agree that the digestive granules vary in 

 size and shape during the gastriolar cycle, ranging from minute spherules 

 to relatively large rods. Both vital stains and metallic impregnation show 

 a homogeneous structure, and the deformation of these granules either 





I 



Figure 31. The association of the gastrioles and the digestive granules in Ichthyoph- 

 thirius multifiliis. (From MacLennan, 1936.) 



from other cytoplasmic granules or from outside pressure show that 

 they have a soft, semifluid consistency. Volkonsky (1934) has found 

 that the morphology of the gastriole varies in the same species with the 

 food used. In Acanthamoeha he was able to induce the formation of 

 large granules, small granules, or a homogeneous rim stainable with 

 neutral red, by varying the food used. No digestive granules were formed 

 around vacuoles which contained only starch. 



The penetration of the digestive granules into the vacuole was not 

 observed by Koehring (1930), Hall and Dunihue (1931), Dunihue 

 (1931), or Hall and Nigrelli (1930), and the suggestion was made 

 that the granules in the food vacuole are derived from food particles 



