132 CYTOPLASMIC INCLUSIONS 



in the formation of gastrioles, new granules are formed in the cyto- 

 plasm. The digestive granules in Ichthyophthmus were observed by 

 MacLennan (1936) to arise de novo in direct contact with the ingested 

 particles of food. Final evidence of their de novo origin was furnished 

 by the fact that no digestive granules are present in the encysted stage, 

 after the gastrioles which were formed during the feeding stage have 

 disappeared. Volkonsky suggests that the materials of the digestive 

 granule exist in the cytoplasm in a diffuse state. In the hypermastigote 

 flagellates this material is concentrated in dissolved form in the gastrioles; 

 in Flabellula the materials are first concentrated in vacuoles, which con- 

 tribute the fluid part of the gastrioles; in the more common cases, the 

 materials are condensed to form digestive granules. We must not for- 

 get, however, that not all the digestive reactions result in granules, since 

 dipeptidase in Amoeba is independent of any granules. Whatever the 

 specific morphology of the reaction, whenever the cytoplasmic equilib- 

 rium is disturbed by the ingestion of food there is an effective mobiliza- 

 tion of this material to cope with the ingested food. Volkonsky calls 

 these varied changes the "vacuolar reaction," an extremely useful term, 

 but since we reject the term vacuome, "gastriolar reaction" would be 

 more appropriate. 



Segregation Granules 



The segregation granules are bodies which are able to concentrate, 

 accumulate, and store within themselves vital dyes, proteins, and other 

 materials. Unlike the definitions of most cytoplasmic granules, this 

 definition is based upon function rather than upon morphology or 

 staining reactions. The evidence for this definition is due largely to the 

 work of Kedrowsky (1931-33) on Opalina, Spirostomum, and other 

 ciliates. Since the functions of most of the granules stainable with 

 neutral red have not been demonstrated, the work on Opalina will be 

 discussed first and granules in other Protozoa considered in the light of 

 this work. The accumulation of vital dyes in higher concentration than 

 they occur in the medium is, of course, one piece of evidence of the 

 segregating ability, even if this has not been demonstrated with the 

 materials which enter into the metabolism of the cell. 



The segregation bodies of Opalina (Figs. 32-35) are the external 

 layer of granules or ectosomes and have been identified as Golgi bodies 



