788 SUMMARY OF CURRENT RESEARCHES RELATING TO 



respecting tlio fructification of bacteria is more correct than that at pre- 

 sent adopted, which was promulgated by de Bary and Hueppe. This 

 doctrine, which also served as a means of classification, subdivided 

 bacteria into the cudosporous and the arthrosporous, according as on the 

 j>lasma there arose small, refracting globular bodies surrounde 1 by a 

 definite membrane, which were set free from the parent cell by some 

 process of softening of the parental cell membrane or not. When these 

 spores found suitable conditions, they lost their refracting qualities, their 

 investing membrane swelled up, and they began to assume the appear- 

 ance of the predecessor from which they had sprung. In the arthro- 

 sporous bacteria it was understood that any single individual, without 

 going tlirough the process of endogenous formation, was able to assume 

 a reproductive condition, and thus start a new series similar to that from 

 which itself had been developed. 



The micrococcus selected by the author was the coccus which 

 lias been long associated with the ammoniacal fermentation of urine. 

 On account of its cruciform fission the author calls it Merista urese. 

 Notwithstanding that this urinary ferment had been subjected to search- 

 ing^ investigation (Pasteur, Leube, Cohn, &c.), spore-formation had not 

 been observed, and yet spores are regularly formed as soon as the 

 urinary fermentation is drawing to a close. When added to sterilized 

 urine, there are found at the commencement of the process, and as long as 

 fermentation is energetic, relatively largo cocci of an oval or elliptical 

 form, the long diameter of which varies from 1 * 5 to 2 • 2 /x, and the short 

 from 0- 8 to 1 • 2 /x. Dividing cruciformly they form diplo- or tetra-cocci 

 which may accumulate into irregular heaps or short<5r or longer chains. 

 Vef^etation having come to an end, the relatively largo form of coccus 

 gives place to a much smaller spherical cell which shows special 

 difi"erences from the first kind. The one sort is large, strongly refracting, 

 and invested in a firm dark membrane, the others, which show several 

 gradations of size, have pale contents and no noticeable contour. The 

 bright, refracting cells are really spores, the pallid cells are in a condi- 

 tion of involution, that is, are dead vegetative cocci. 



The spores are distinguished by their great resistance to injury. 

 They withstand prolonged drying, and are only killed by a temperature 

 of 100^ C, resisting 90^ C. for a minute, and 80^ C. for 2 minutes. 

 Dried under a cover-glass, they show a double outline, the outer of 

 which is dark and thick, the inner thin and delicate. Placed in fresh 

 urine, they germinate with appearances similar to endogenous spores, 

 becoming pale, assuming the form and size of the vegetative cocci, and 

 multiplying by cruciform fission. With regard to the spore membrane, 

 it could not be ascertained by direct observation if it originated as a 

 thickening of the primary membrane of the vegetative cell, or was a new 

 formation, the parental cell membrane being dissolved. Apart from this, 

 which the author considers of little importance, the spores of Merista urese 

 behave so much like the endogenous spores of other bacteria that their endo- 

 genous origin must be conceded. This view is strengthened by observa- 

 tions on bacteria obtained from the excrement of cattle. In their early 

 stage in pure cultivations they are short rods 2 • 5 to 4 ^ long, and 1 • 

 to 1 • 5 /A broad, usually single or in pairs, more rarely in very short 

 chains. On the 3rd or 4th day a dirty white scum forms on the surface, 

 and this afterwards falls to the bottom. It is in this scum that tho 

 spore-formation takes place. Tho rodlets become thickened, and at tho 



