26 FORM AND DIMENSIONS 



"bacteria: " and a special one, referring only to a particular form of growth, as 

 just mentioned. 



A bacterial cell of the bacillus type which, during a certain physiological 



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FIG. 4. Illustrations of the manifold variety in size and form of different bacteria. 



Kxcept A 4 and A 5 , all the other illustrations are representations of equally magnified 

 bacteria from a single drop of putrescent blood. (After P. Baumgarten.) Mag. 950. Those in 

 A are all symmetrical cells, those in B are elongated. 



A. i. Cocci (micrococcns) of various sizes. 



2. Diplococci of various sizes. 



3. Streptococci of various sizes. 



4. Micrococcus tetragonus (from a pure culture). Mag. 950. 



5. Sarcina ventriculi. Mag. 700. 



6. Staphylococci. 



B. i, 2, 4. Separate long rods of various lengths and breadths. 

 3. Short rods, partly of biscuit form. 

 5- Chains, composed of either short or long rods. 

 6. Long threads. 



process (to be studied later on under the name of " spore formation "), swells out 

 like a spindle or club, is generally termed a clostriclium. 



If the rod is arched like a bow or bent in the form of a comma, it is spoken 

 of as a vibrio, and if the bends be repeated several times, then a wavy kind of 

 growth denoted spirochaete ensues. When the bend departs from the level 

 plane and shapes itself in such a manner that it can be applied to the surface of 

 a cone or cylinder, the type of growth becomes spiral, and is designated spirillum. 



