CYTOPLASMIC INCLUSIONS 133 



or as mitochondria by various authors, since they respond to some of 

 the Golgi and mitochondrial techniques, although they are not stained 

 specifically with Janus green B. Kedrowsky described four main morpho- 

 logical types — fine dispersed granules, large granules, alveoli, and 

 heteromorphic granules (Figs. 32-35). In some cases the dispersion of 

 granules is so accentuated that they lose their identity as granules. These 

 changes in morphology are associated under natural conditions with the 

 seasons of the year; for instance, the heteromorphic types are common 

 in the spring and early summer, and the large granular type is found 

 in the early spring. There is some variation between populations of 

 different frogs in the same season, but all members of the same popula- 





52 



?t 



33 ^ 35 



Figures 32-35. Basic morphological variations in the segregation granules of Opalina 

 ranarum. Semischematic. (After Kedrowsky, 1931e): Figure 32. Dispersed type; Figure 

 33, homomorphic granular type; Figure 34, alveolar type; Figure 35, heteromorphic 

 granular type. 



tion have essentially the same type of granules. These different forms 

 can be produced experimentally by changing the culture medium. The 

 colloidally dispersed type is typical of amino-acid cultures. In distilled 

 water, each ectosome swells and becomes a watery vacuole. The hetero- 

 morphic type is found in cultures which contain defibrinated and hemo- 

 lysed blood. These changes, which occur both naturally and in artificial 

 media, may well account for the disagreement among cytologists both 

 as to the morphology and the identification of these granules. 



The segregation bodies of Opalina are not permanent organelles. As 

 indicated above, they may disperse homogeneously through the ecto- 

 plasm, which then takes a general pale stain with neutral red, and no 

 method applied at this stage shows any indication of a remnant of the 

 originally discrete granules. If the bodies are loaded with protein com- 

 pounds of metals, such as silver, they may finally be extruded from the 

 surface and be replaced by granules which arise de novo. 



