CHAPTER II, 
MORPHOLOGY OF BACTERIA. 
BACTERIA ate minute, unicellular, vegetable or- 
ganisms. ‘They consist of a sharply defined mass of 
protoplasm which reacts to anilin stains very much 
like the nuclei of other cells, and outside of this 
a more or less well-developed envelope. They are 
classified according to their form into three main 
groups, the spherical cocci, the rod-shaped bacilli, 
and the curved or spiral spirilla. 
a b 
t) eo 
g h 
CO) O 
® oO 
Fic. 9.—Diagram illustrating the morphology of the 
cocci : @, coccus or micrococcus ; 4, diplococcus ; ¢, d, strep- 
tococci ; ¢, f, tetragenococci or merismopedia ; g, 2, modes 
of division of cocci; z, sarcina; 7, coceus with flagella; 4, 
staphylococci (McFarland). 
I. Demonstration of Form. 
(a) Make hanging-drop and stained preparations 
from cultures of cocci, bacilli, and spirilla. 
(6) Examine with the } inch or with the oil- 
immersion lens. 
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