BACTERIA. 



27 



31); often self-motile). Branched filaments, with false branching 

 like many Scytonemacece, are found in Cladothrix (Fig. 30 B, G). 



4. SPIRAL FORMS : Rod-like or filamentous bodies, which more 

 or less strongly resemble a corkscrew with a spiral rising to the 

 left. In general these are termed Spirilla (Fig. 23) ; very attenu- 

 ated spirals, Vibriones (standing next to Fig. 30 M) ; if the filaments 

 are slender and flexible with a closely wound spiral, Spirochcetce 

 (Fig. 24). 



5. The MERISMOPEDITJM- 

 FORM, consisting of rounded 

 cells arranged in one plane, 

 generally in groups of four, and 

 produced by divisions perpen- 

 dicular to each other. 



6. The SARCINA-FORM, con- 

 sisting of roundish cells which 

 are produced by cellular divi- 

 sion in all the three directions 

 of space, united into globular 

 or ovoid masses ("parcels") 

 e.g. Sarcina ventriculi (Figs. 



FIG. 24. Spirochcete obermeieri, in active 

 motion (b)and shortly before the termination 

 of the fever (c) ; a blood corpuscles. 



25, 26). 



All Bacteria are unicellular. In the case of the micrococci this 

 is self-evident, but in the " rod," " thread," and " spiral " Bacteria, 

 very often numerous cells remain united together and their indi- 

 vidual elements can only be recognised by the use of special re- 

 agents. 



FIG. 25. Sarcina ventriculi. One sur- 

 face only is generally seen. Those cells 

 which are drawn with double contour are 

 seen with the correct focus, and more 

 distinctly than those cells lying deeper 

 drawn with single contour. 



FIG. 26. Sarcina minuta : a-d succes- 

 sive stages of one individual (from 4-10 

 p.m.) ; / an individual of 32 cells. 



The condition termed " Zoogloea," which reminds us of Nostoc, is 

 produced by the cells becoming strongly mucilaginous. A number 

 of individuals in active division are found embedded in a mass of 

 mucilage, which either contains only one, or sometimes more, of 



