10 TEXT-BOOK OF BACTEKIOLOGY. 



III. POWERS OF RESISTANCE OP SPORES— MULTIPLICATION 

 OP BACTERIA— 8P0RULATI0N— VARIETIES OP SPORE-FOR- 

 MATION. 



The bacteria multiply by fission; the cell stretches out in the 

 direction of its length, the membrane pushes a partition wall into 

 the interior, and thus brings about the division into two new germs. 

 These, again, can very speedily divide, and the multiplying powers 

 of the bacteria are, in fact, immeasurable. 



If the direction in which the consecutive divisions take place is 

 one and the same, and if the cells after such division remain in con- 

 nection, we see — as we have already seen — those siimple forms of 

 connection known in the case of cocci as streptococci, in the bacilli 

 as threads (apparent threads), leptothrix, etc. These terms are 

 nothing but the expression for the occurrence of growth proceeding 

 in a continued line. Two particularly good examples of these two 

 classes are seen in uncolored preparations of the erysipelas micro- 

 cocci (in long bead-like chains) and in anthrax bacilli, grown out 

 into threads, which traverse the entire microscopic field of vision. 



A remarkable difference between the two will be apparent. 



In the cocci, notwithstanding the close connection in their linear 

 arrangement, we will be able to recognize the separate members. 

 We can see everywhere the points of division, slight contractions, 

 something like articulations, but in the anthrax threads we can 

 perceive a point of division here and there in consequence of the 

 difference of refractive power, and we must adopt some other means 

 to demonstrate that such threads consist of many little rods placed 

 end to end. 



The fission of bacteria generally proceeds in one direction, occa- 

 sionally also in two places at right angles to each other, and, lastlj'-, 

 in all three directions of space. The last two phenomena have as 

 yet been observed with certainty only in the micrococci; in one case 

 we have the so-called tetrad forms; in the other those peculiar 

 groups known as sarcinae are formed. Doubtless from clinical 

 studies the Sarcina ventriculi will be remembered, which may serve 

 to illustrate the cubic, or bale-like, packets formed by these micro- 

 cocci. 



The bacteria are able to propagate — which does not mean to 

 multiply immediately — bj' another means than that of division. 

 In quite a number of bacilli, and also in some few spirilli, genuine 

 fructification, or the formation of spores in the interior of the cell, 

 has been observed. 



The fact, as such, has been seen in many bacteria, but it has as 



