ELEMENTS OF MICROBIAL CYTOLOGY 



REPRODUCTION OF THE CELL 



VARIOUS PROCESSES OF REPRODUCTION. Reproduction of microbes 

 is affected by various processes; the cell may reproduce itself by trans- 

 verse or longitudinal fission, binary division, schizogony (bacteria, 

 flagellata, molds, Figs. 6, A; 18; 20, A). This is by far the most fre- 

 quent. It sometimes, however, divides itself by budding, gemmula- 

 tion (Yeast, Fig. 3); that is, by the formation of a small protuberance 

 which separates itself from the mother cell as a small daughter cell 

 which, once free, grows slowly to maturity. 



Finally, a last process and a very frequent one is the formation of 

 internal spores, or sporogony (Fig. 19). The nucleus undergoes a 





FIG. 1 8. Schizogony in Amoeba 

 polypodia with amitotic division 

 of the nucleus. (After Schnlze 

 and Lange.} 



FIG. 19. Sporogony. A, Formation 



of spores in Saccharomyces cerevisice. B, 



Formation of spores in B. mycoides. (After 



Guilliermond.) C. Formation of spores in 



Lencocytozoon lovati. (After Fantham.) 



certain number of divisions, and the cytoplasm divides itself inside the 

 cell in as many small cells as there are nuclei. These cells become 

 spores and are set free by a rupture in the wall of the mother cell. 

 Sometimes all the cytoplasm of the mother cell divides into spores, and 

 sometimes only a part of the cytoplasm is used, the rest epiplasm 

 serving as nourishment to the spores during their growth. 



Whatever the means by which the cell reproduces itself, cyto- 

 plasmic changes and nuclear changes take place at the same time. 

 The most important of the cytoplasmic changes is the distribution 

 of the chondrium structure between two daughter cells, often preced- 

 ing the division of this cytoplasmic structure (Fig. 9). 



