CYTOPLASMIC INCLUSIONS 121 



nor in the crystals since most of these are in the centrifugal end which 

 would thus have the highest enzymatic activity. They also ruled out a 

 localization in the digestive vacuoles by a demonstration that the enzyme 

 content of hungry and feeding Amoeba, with a resultant difference in 

 the number of vacuoles, is the same. The only structures the distribu- 

 tion of which after centrifuging corresponds with the distribution of 

 amylase are the mitochondria. The study of the centrifuged Amoeba 

 presents many difficulties, since the stratification is never complete and 

 there is always some mixing between the finishing of centrifuging and 

 cutting the amoeba in parts, but the further use and development of these 

 methods and their use in species in which stratification is complete 

 will undoubtedly aid in the complete analysis of mitochondria and other 

 cytoplasmic granules. 



The theory that mitochondria are concerned with cellular respiration 

 has led to attempts to identify in the mitochondria the materials known 

 to be active in this respect. One of these is glutathione, in which the 

 physiologically active group is sulfhydril, demonstrable cytochemically 

 by the sodium nitroprusside reaction. Joyet-Lavergne (1927-29) found 

 that the mitochondria of Sporozoa give a positive reaction with sodium 

 nitroprusside, and this was confirmed by Cowdry and Scott (1928) in 

 Plasmodium. Chalkley (1937), however, found that the strongest re- 

 action in vegetative Amoeba is in the nucleus and that at the metaphase 

 this material is poured into the cytoplasm. Some granules in the nucleus 

 gvwQ a particularly strong reaction, but in the cytoplasm the coloration 

 is diffuse. These results of Chalkley's extensive work on glutathione in 

 Amoeba suggest the desirability of a reinvestigation of the Sporozoa, 

 and certainly indicate that the materials containing the sulfhydryl group 

 are not always localized in the mitochondria. Joyet-Lavergne (1934) has 

 also shown that the mitochondria give a strong reaction with the anti- 

 mony trichloride test for vitamin A, and concludes that this is a part of 

 the respiratory mechanism along with glutathione. Although respiration 

 cannot be discussed in detail here, it should be pointed out that the 

 glutathione-vitamin A theory presents many difficulties and the system 

 more usually accepted is glutathione-ascorbic acid (Holmes, 1937). 

 Bourne and Allen (1935) and Bourne (1936) have demonstrated the 

 concentration of ascorbic acid in cytoplasmic granules by the acetic- 

 silver-nitrate method, but unfortunately have not correlated these with 



