I CYTOPLASM 173 



nucleoprotein, flavoprotein, triglycerides, lecithin, sterine, vitamin A 

 and 80-90% water. They contain the ribonucleic acid of the cytoplasm 

 (Jeener, 1948). According to the view of Caspersson (1941), they 

 are involved in protein synthesis. 



As metabolic centres they are analogous to the mitochondria or 

 chondriosomes, which, however, are microscopic particles and repre- 

 sent a special system in the cell which is designated as chondriome 

 (GuiLLiERMOND, Mangenot and Plantefol, 1933; Bourne, 1945). 

 The mitochondria of guinea pig liver tissue can be isolated (Hoerr, 

 1943) and analyzed. They are of lipidic nature (43.6%) but contain 

 at the same dme two proteins of different I.E. P. They are free of 

 lecithin and cephalin (Bensley and Hoerr, 1934). Faure-Fremiet 

 (1946) gives for the same material somewhat different figures: Protein 

 64.6%, glycerides 28.8%, lecithin and cephalin 4.2%, cholesterol 

 2.25 %. At any rate there is no nucleic acid present. This is confirmed 

 by the lack of UV absorption (Monne, 1948). According to Monne 

 (1942 b), the mitochondria may be strongly hydrophilic. 



The rodlet shape of the so-called chondrioconts and the double 

 refraction of the filamentous mitochondria from the intestinal cells of 

 Ascaris megalocephala (Giroud, 1928) indicate an inner structure 

 resembling a mesophase. Originally Bensley (1937) thought that the 

 chondriosomes might be merely coacervates. Claude and Fullam's 

 (1945) electron micrograms of fixed chondriosomes show a lipid 

 cortex and a watery, less dense central zone. In addition Muhle- 

 thaler, Muller and Zollinger (1950) have found that, in kidney 

 cells, they are coated with a distinct submicroscopic membrane. 



In recent publications the mitochondria are considered as important 

 bodies with special physiological functions (Claude, 1944), as certain 

 enzymes are fixed on them. Hogeboom, Claude and Hotchkiss (1946) 

 found cytochrome oxidase, and Leuthardt (1949) was able to localize 

 the enzymes of the tricarboxyHc acid cycle on the liver mitochondria. 

 Muller and Leuthardt (1950) and Brenner (1949) have demon- 

 strated that the mitochondria of intact lymphocytes perform oxidation 

 — reduction reactions. This means that the respiration is assigned to 

 these bodies. The fact that the mitochondria are dispersed throughout 

 the cytoplasm would account for continuing respiration of parts dis- 

 sected from a living cell. 



It is probable that new mitochondria originate exclusively from 



