ELEMENTS OF MICROBIAL CYTOLOGY 19 



plasm appears to be composed largely of protein substances and of 

 diverse lipoid substances in a state of colloidal- solution. It varies 

 widely according to circumstances, consequently it may be useless to 

 search for any definite structure. In many microorganisms, as for 

 example the protozoa, there is on the periphery of the cell a hyalin zone 

 which is called the ectoplasm to distinguish it from the rest of the 

 cytoplasm, the endoplasm (Fig. 17). 



Chondriosomes. Recent research has demonstrated special func- 

 tioning bodies in the cytoplasm, the mitochondria, which seem to be 

 the constructive elements of cytoplasm. They are a part of its struc- 

 ture, and are supposed to play an important physiological role in the 

 cell. These structures, visible in the living organism, but stained 



" I 'I , 



I 



f 



mu"' - 



K * \u\\ui' 



\ /* - i\y 



$Ky A * 



FIG. 8. Glaucoma piriformis, FIG. 9. Division of micronu- 



infusorian with (N) ' macronu- cleus and of the chondriosomes 



cleus, (n) micronucleus, (ch) in Carchesium polypinum, infu- 



mitochondria, (vp) pulsating sorian. (After Faure-Fremiet.) 

 vacuole. (After Faure-Fre- 

 miet.) 



only by a special process, are sometimes in the form of small isolated 

 granules (granular mitochondria, Fig. 8, B), or of small threads (thread- 

 mitochondria} or sometimes of rods much like certain bacilli (rod- 

 mitochondria, Fig. 8, A). These forms frequently change from one to 

 the other. The granular mitochondrium is able to elongate itself into 

 a rod which is itself capable of dividing up into thread-mitochondria. 

 All the mitochondria of one cell are called the chondrium. These 

 structures seem to be made up of lipoidal substance and phosphates of 

 albumin. 



The mitochondria cannot generate themselves directly from the 

 cytoplasm, but are formed always from preexisting mitochondria by 

 division. They apparently transmit themselves, after having divided, 

 from the egg to the adult individual, and from the adult individual 

 to the egg (Fig. 9). 



