392 



ACETIC FERMENTATION. 



occurs, and is already noticeable at the end of a few hours. The 

 short rods, about 2 /x long and i //- broad, of which the chains of 

 the seed were composed, begin to elongate, and at the end of 

 eight to nine hours none but long rods are' found, some of these 

 being already disconnected, others still retaining the chain form. 

 The latter also finally become dismembered, so that after a further 

 four hours none but elongated cells, 40 p and more in length, are 

 present. These now continue to grow, and in twenty -four hours 

 from the commencement of the experiment long threads (Fig. 85), 



some of them measuring 

 200 p in length, are found 

 exclusively. 



A fresh modification 

 of form sets in as soon 

 as these long threads are 

 exposed to the original 

 temperature of 34 C. 

 they begin to bulge. 

 These forms (Fig. 86) 

 can be already noticed at 

 the end of four hours, 

 and their number rapidly 

 increases from that time 

 onward. At about the 

 same time other portions 

 of the threads begin to 

 break up into fragments, 

 the disruption beginning 

 indifferently at either or 

 both the extremities, or 

 in the middle of the 

 thread, which is thus 

 modified into a chain of 

 short rods, or one exhibit- 

 ing both long rods, un- 

 altered portions of threads, 

 and bulged articulations ; 

 in short, great diversity 

 prevails. All intermediate stages of the last-named forms, between 

 the very frequent spindle cells on the one hand, and pear-shaped 

 rounded forms on the other, are met with. Globular cells, measuring 

 up to 10 /A in diameter, are also by no means rare. 



Finally, the threads become entirely dismembered into short 

 rods (Fig. 87), even the bulged cells undergoing this conversion, 

 and leaving only the thickest portion (Fig. 88) unchanged. This 

 portion eventually, after the filamentous ends on either side have 

 broken up into short rods, collapses in the surrounding liquid and 

 dissolves. An examination made after the lapse of twenty-fou 



FIG. 88. Bacterium Pasteurianum. 



Residue of swollen long threads after a sojourn 

 of one to two days in " doppel-bier " at 34 C. 

 In a the pear-shaped swelling has tapered 

 out into two thin threads. In b the lower of 

 these has divided into short rods. In c the 

 swelling has begun to disintegrate, a part of 

 the plasmal cell contents escaping. In d the 

 evacuation is complete, only the thick cell 

 wall being left. e. spindle-shaped swollen 

 form, with two long threads undergoing in- 

 cipient subdivision. Magn. 1000. (After 

 Hansen.) 



