CYTOPLASMIC INCLUSIONS 165 



analysis, solubility, and form shows that the bipyramidal type probably 

 consists of a magnesium salt of a substituted glycine. The plate-like 

 crystals are insoluble in a saturated solution of leucine, and in structure 

 resemble leucine crystals. If the crystals are removed by centrifuging 

 and the Amoeba is then put in a solution which contains amino acids 

 and egg albumin, the platelets are formed in the vacuoles which con- 

 tain leucine, while the bipyramidal crystals are formed in all solutions. 

 "Crystals are normally formed from amino acids derived from food dur- 

 ing digestion" (Mast and Doyle, 1935b). These crystals decrease in 

 number just before the refractive bodies increase in number, indicating 

 that the crystals are an intermediate stage in the transfer of food from 

 the food vacuoles to the lipoprotein refractive bodies. 



The chromatoidal bodies of various parasitic amoebae, are intensely 

 basophilic structures, the fixing and staining reactions of which suggest 

 a protein composition. They possess neither chromatin nor free nucleic 

 acid (Reichenow, 1928), so are not volutin; but they are similar in 

 their reactions to the protein bodies of ciliates. Since they disappear dur- 

 ing encystment they are reserve bodies. 



The reserve proteins are often found in combination with other ma- 

 terials. In Amoeba, lipoids and proteins are bound together in the re- 

 fractive bodies (Mast and Doyle, 1935a). In Act'mosphaerium, granules 

 of glycoproteid are present (Rumjantzew and Wermel, 1925). Similar 

 inclusions are found in Ophryoglena (Zinger, 1928). In the Foet- 

 tingeriidae the protein reserves have the characteristics of the vitellin of 

 the hen's Qgg and in Polysp/ra there is a single central mass consisting of 

 protein associated with a carotenoid (Chatton, Parat, and Lwoff, 1927). 

 The protein portion alone is used, the carotenoid remaining in the old 

 cyst, and finally disappearing during encystment. 



The protein bodies which are found throughout the Protozoa vary 

 greatly in their specific structure and composition. This variation, with 

 the resulting variation in staining reactions, has resulted in a complicated 

 nomenclature with the usage of terms proposed by each author. The 

 term chromidia is so definitely bound up with disproved theories that 

 it should be dropped. Volutin should either be dropped or definitely 

 restricted to metachromatic granules which respond to Feulgen's stain 

 when used without hydrolysis. Whenever the function is that of a re- 

 serve, as in the majority of known cases, I believe these granules should 



