220 CLASSIFICATION OF THE MICRO-ORGANISMS. 



gelatine plates Lave attained the size of 0*4 O6 mm., 

 are of a dark chrome yellow colour, round or oval ; the 

 superficial ones have a smooth wax-like surface, measure 

 ultimately J 1 mm., and project at their middle some- 

 what above the gelatine. Under a low power the deep 

 colonies present a sharp, smooth contour, and a uniform 

 dark olive green colour ; in the superficial ones the 

 colour becomes lighter and more of a greyish yellow 

 tinge towards the margin. In the puncture it is not 

 till after 6 8 days that a row of minute yellow colonies, 

 which form balls and remain isolated, can be noticed. 

 The gelatine is not at all liquefied. Less common than 

 the forms mentioned before ; often occurs along with 

 M. cinnabareus. 



Micrococcus coronatus.* 



Cocci somewhat more than 1 /*. in diameter, single 

 or arranged in short chains or masses.^-On gelatine 

 plates the colonies appear on the second day as whitish 

 yellow points ; those which lie superficially project some- 

 Avhat above the gelatine, and are surrounded by a sKghtly 

 depressed zone. The deep colonies appear, when magni- 

 fied 80 times, as very dark opaque sharply defined plates. 

 In the superficial ones the remains of the deep colonies 

 are altered in a peculiar manner ; at two or three places 

 of the disc, which was formerly circular, short pointed 

 processes project at equal intervals frorn the periphery ; 

 the remains of the deep colonies which have become 

 broadened out in this peculiar manner are of a dark 

 colour, but are now surrounded by a broad yellowish- 

 brown border, the superficial extension of the cocci. 

 On the following day the gelatine is liquefied in the 

 neighbourhood of this border ; a ring has formed at a 

 certain distance from the dark centre, and surrounds 

 the original colony like a crown or halo. At times the 

 colony lies somewhat excentrically in the ring, which is 

 then more of an oval form. Between the ring and the 



* Gottingcr hygienisches Institut. 



