CYTOPLASMIC INCLUSIONS 159 



of Amoeba hydroxena contain two different materials (Figs. 58, 59) 

 and on the basis of Best's and Fischer's methods have been interpreted 

 as granules of glycogen embedded in glycoprotein. 



The decrease in glycogen or paraglycogen during hunger or encyst- 

 ment, and its storage during the feeding stages, has been noted so often 

 that detailed descriptions of observations under controlled conditions 

 are rare. The glycogen in Stentor is deposited during low temperatures 

 and utilized at higher temperatures, and this process is accelerated by 

 starvation (Zhinkin, 1930). Fat, rather than glycogen, is deposited, if 

 the oxygen tension is lowered. Under such conditions some of the car- 

 bohydrate is probably converted into fat. In Trkhonympha also, avail- 

 able food, oxygen tension, and temperature affects the amount of glyco- 

 gen present ( Yamasaki, 1937b) . The cytoplasm of this species is divided 

 into two parts by a fibrillar basket, which suspends the nucleus from the 

 anterior cone of the body and separates this portion from the rounded 

 posterior part in which the food vacuoles are formed. Both regions 

 normally contain glycogen (Fig. 63), but during starvation the glycogen 

 in the posterior part disappears first, the glycogen in the anterior part 

 then diminishes and disappears, and the death of the organism follows 

 shortly. Similar results are observed at high temperatures, or with oxy- 

 genation at room temperature. However, when the termites are oxygen- 

 ated at low temperatures (Fig. 64), the glycogen in the posterior por- 

 tion often shows little change, but the portion anterior to the nucleus 

 disappears rapidly. As soon as the glycogen in the corbula disappears the 

 protozoan dies, even though glycogen remains in the body region. 

 Yamasaki states that the posterior region is simply one of synthesis and 

 storage, while the anterior region is the region of consumption. He 

 concludes that defaunation by oxygen is due not only to, toxicity but also 

 to a depletion of the glycogen available for the nucleus and motor or- 

 ganelles. 



Trypanosoma evansi possesses no glycogen and, since it possesses no 

 amylase, is not able to synthesize it (Krijgsman, 1936). Other trypano- 

 somes do deposit glycogen, but at best it forms an insignificant reserve, 

 since trypanosomes may use three times their body weight in sugar in 

 twenty-four hours (von Brand, 1938). In this case the glycogen re- 

 serves of the trypanosomes are the liver glycogen of the host. 



