M()l{lMl()l,()(;^ . ('^■T()l,()(;^■. and i,ifI'; ("vcm.ms 



73 



ami shows ict'i-inticiit liraiuilcs piohahly con- 

 sisting ot" \()lutin (I Jcskc). Fat ^raiuilcs and 

 occasional vacuoles containin<i; chroniotropic 

 ji;ranules were observed by (irigonikis (lOi^l) 

 in the thallus of the or<j;anisnis {^rown on an 

 agar medium containing glycerol and pep- 

 tone. 



Our knowledge of the moi'])hology of ac- 

 tinomycetes has recently l)een enlargexl 

 greatly by studies of their cytology, espe- 

 cially through the use of the electron micro- 

 scope. Disco^•eries of chromatic substance 

 (Schaede, von Plotho, 1940), of lipids (Krik- 

 son, 1947) and of the chemical comiM)sition of 

 the cells (Romano and Sohlei', C'unuuins and 

 Harris) have further contributed to a better 

 understanding of their structural properties. 



Electron microscope studies of the mech- 

 anism of spore formation by members of the 

 genus Streptomyces tended to confirm the 

 view of Lachner-Sandoval, presented as far 

 back as 1898. According to Vernon (1955), 



FiGtRE 33. (lermiiiation of a streptomyces 

 spore, as shown by electron microscopy, X3S,000 

 (Carvajal, F. Mycologia 38: 589, 1946). 



\ 



Figure 34. S. griseus: j)rimary niNcclium at 40 hours from suhnicrficd culture, showing germinating 

 initial cell. Visual light, X 2000 (Reproduced from: Dickenson, P. H. aiuLMacdonald, K. I). J. (ien. .Micro- 

 biol. 13: 89, 1955). 



