SCHIZOM YCE TES 



451 



which have been termed Bacillus Cohn (long rods), and specially Bac- 

 terium Cohn (short rods) ; the shortly coiled forms are known as Vibrio 

 Cohn ; and the spiral forms have received the names of Spirillum 

 Ehrenb., Spirochceta Ehrenb., &c., and the very elongated filiform 

 forms are Leptothrix Ktz., Beggiatoa Trev. &c. Involution forms are 

 swollen bladder-like structures of irregular outline probably produced by 

 malnutrition. These growth-forms of cells or of individuals either occur 

 free, or in the form of filaments, or more seldom of flat surfaces or 

 cube-like packets. Large gelatinous masses called Zpoglma, composed of 

 numerous individuals of these growth-forms, occur in various situations 

 such as the surfaces of fluids and solids, or they may be found 

 suspended in fluids. 



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Fig. 379. — Bctcillus Fitzianus Zopf. Transition forms from round cocci to rods 

 d^ with spores ( X 4,000). (After Buchner.) 



Such forms of Bacteria are grouped into two divisions, viz. those 

 which form their spores endogenously, the Endosporous Bacteria, and 

 those which have no such mode of forming spores, the Arthrosporous 

 Bacteria. This classification, which can hardly be regarded as finally 

 satisfactory, corresponds, at all events, with the state of our knowledge 

 of the course of development of Bacteria. 



Endosporous multiplication is accomplished by the formation within 

 a cell of a minute, granule-like body, which gradually enlarges, while 

 the surrounding protoplasm disappears until it reaches its mature form 



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