122 CYTOPLASMIC INCLUSIONS 



any particular type of granules. Daniels (1938) used this method in 

 gregarines, but although she was able to demonstrate granular accumula- 

 tions in the cells of the gut, the gregarines remained clear. 



The functions ascribed to mitochondria in the Protozoa may be 

 grouped under two main headings: synthesis (or segregation), and 

 respiration. The first group includes a number of activities, all of which 

 involve the accumulation of materials and in some cases the synthesis 

 of new products from these raw materials. Examples of this type of 

 function for which there is definite evidence are the secretion of reserve 

 bodies, a digestive function in connection with the gastrioles, excretory 

 function in connection with the contractile vacuoles, and the transport of 

 materials from one organelle to another. Respiration also might be 

 considered to fall in this category, since it would depend upon the ac- 

 cumulation in the mitochondria of the substances responsible for the 

 oxidation-reduction processes of the cell. 



The secretion of reserve bodies is cytologically the easiest phase of 

 accumulation to demonstrate. Faure-Fremiet described the formation 

 of deutoplasmic granules by direct transformation of mitochondria, as 

 well as by the more common method of segregation adjacent to or 

 within the mitochondria which retain their identity. Joyet-Lavergne 

 (1926a) occasionally found a relationship of this type between the 

 mitochondria and paraglycogen and always found that protein granules 

 possessed a mitochondrial cap (Fig. 27), but denied that this indicated 

 anything more than a casual relationship. Horning (1925) described 

 mitochondrial rims around the protein granules in Opalina (this identi- 

 fication of mitochondria is denied by Kedrowsky, 1931b) and accepts 

 it as evidence of secretory activity. MacLennan (1936) described the 

 origin of paraglycogen in the center of spherical mitochondria (Fig. 17) . 

 The identification of these granules was made not only with the usual 

 permanent stains for mitochondria, but with specific microchemical 

 stains (Sudan III, Nile blue sulfate, iodine, chlor-zinc-iodide), and 

 their growth observed in live specimens stained with Janus green. The 

 fact that the paraglycogen first appears as a center in a solid mito- 

 chondrial sphere refutes the usual suggestions that the secretion merely 

 happens to be in contact with the mitochondria and that there is no 

 real connection between the two. There is no evidence as yet to show 

 whether these visible secretions are actually synthesized by the mito- 



