1891.] MICllOSCOriCAL JOURISAL. 138 



by heating at 65° C. for three hours each dav for four consecutive days. 

 It remained clear and acid after standing for several days at a tempera- 

 ture of 36" C 



(3) Acid gelatine plus urea. — This is prepared in precisely the 

 same manner as the acid bouillon, with the addition of 10 per cent, 

 gelatine, which is added before the beef-infusion is boiled. The urea 

 is added to the liquid gelatine after it is filtered. It is preserved in 

 sterile cotton-plugged test tubes and sterilized by the same method as 

 the bouillon after which it remained clear and acid in reaction. 



Description of Ne\v Germs, — In the light that we already have 

 concerning this class of organisms, and in the present unsettled condi- 

 tion of bacteriological classification, it seems more desirable to omit 

 the assigning of specific names to the micrococci about to be described, 

 but simply tlifi'erentiate them with reference to their morphological 

 characters and their growth in certain culture media. They will, 

 therefore, be designated by the first letters of the alphabet, as micro- 

 coccus A, micrococcus B, etc. In comparing the morphological and 

 cultural characters of these bacteria with the description of the micro- 

 cocci described by Pasteur, Fliigge, and Miquel I have failed to find 

 sufficient resemblances to establish their identity. Their effect upon 

 urea in nutrient solutions is, however, practically the same. 



Micrococcus A. — A micrococcus varying in diameter from 0.6 //. to 

 1.2 ,". ; average 0.9 //. When grown in bouillon the cocci most usually 

 appear in small clumps and in the form of diplococci. There seems to 

 be a mjirked disposition in the cocci to be closely united in pairs. In 

 acid bouillon they are frequently observed united in short chains. 



Agar (surface growth) at 36° C, — After 24 hours round, convex, 

 grayish colonies appear with a glistening surface and sharply defined 

 border. When they are separated by a distance of one-half inch or 

 more they are about i millimeter in diameter. After growing for sev- 

 eral days the colonies become opaque and whitish, but are otherwise 

 unchanged in appearance. The colonies are quite brittle. The growth 

 in the condensation water is quite vigorous, giving it a clouded appear- 

 ance. 



Gelatine (needle culture). — In nutrient gelatine the growth is quite 

 vigorous at 70" F. Along the needle track, after 24 hours, a grayish, 

 opaque, somewhat granular line appears, which consists of crowded 

 colonies. At the surface the growth is more vigorous, forming an ele- 

 vated glistening band around the needle puncture. This may be due 

 to the greater number of germs collected there. On the second or third 

 day the gelatine begins to liquefy along the entire length of the needle 

 track. At first the liquefaction is generally more rapid on the surface, 

 giving a cone-like appearance to the liquid portion, the base being at 

 the surface. Very often the liquefaction is in the form of a cylinder. 

 The entire mass of gelatine is liquefied in from 8 to 20 days. In a 

 higher temperature (7>° to 80^ F.) the growth is more rapid. The 

 liquid gelatine holds in suspension fine granular masses of germs \ to 

 \ millimeter in diameter. A considerable quantity of a grayish sedi- 

 ment collects in the bottom of the tube ; a fine granular pellicle also 

 forms over the surface. Both the pellicle and sediment are very viscid. 

 The liquefied gelatine will not set, showing that it has become pep- 

 tonized. 



