THE ORGANISMS OF SUPPURATION. i8i 



semi-circular. They are, even in this form, easily to 

 be distinguished from the rodlets, since their cell walls 

 are never parallel for even the smallest part of their 

 length. 



3. Bacillus pyogenes foetidus. 



This organism, though of rare occurrence, is shortly 

 described here, as it is sometimes to be seen in pus. 

 It grows very rapidly on gelatine plates ; even on the 

 second day small white spots may be observed. 

 These quickly grow into large colonies, which may 

 be sometimes as much as 1| cm. in diameter, and 

 which finally coalesce. The colonies are whitish grey 

 in colour, and often somewhat transparent, especially 

 towards their edges, where they are much thiuner. 

 The gelatine is not liquefied. In a puncture culti- 

 vation the bacillus spreads itself out in a similar 

 manner on the surface, but the colony generally 

 appears more transparent, whilst its edges are raised 

 above the surface. All along the track of the needle 

 the growth is insignificant, generally only very small 

 globular colonies, sometimes irregularly confluent, 

 sometimes isolated, are formed. On potatoes thick, 

 slimy, yellow-brown colonies develop (the colouring 

 matter is not always uniform, it is more or less brown or 

 yellow according to the reaction of the potato). The 

 growth upon agar-agar is similar to that upon gelatine, 

 only more vigorous, and the colonies, especially as 

 they grow older, become of a dirty brownish colour. 



