VARIOUS BACILLI. 409 



Bacillus tumescens (Zopf). 



This organism was observed by Zopf on boiled carrots kept 

 fairly moist ; it forms there a tough, wrinkled whitish skin, 

 which consists of small disc-like gelatinous masses. The skin 

 contains narrow rods arranged in zooglaea forms, these rods 

 forming at a later period shorter joints, and in these shorter 

 joints spores. Its other characters are not as yet known. 



Bacillus ulna (Cohn). 



This organism was first observed by Cohn, and then by Praz- 

 mowski, in decoctions of boiled egg albumen, and also under 

 the shell of an egg. They are rods 1'5 to 2 '2 p. in breadth and 

 of varying length, attaining at least 3 p.. ; they are mobile. As 

 regards the formation of threads and spores, they resemble 

 bacillus subtilis ; the spores are 2'5 to 2'8 /*. in length, and 

 over 1 p. in breadth. This organism only grows on soil which 

 is rich in albumen, for example, in decoctions of boiled egg 

 albumen. These fluids become turbid on the day after inocu- 

 lation, and cloudy masses are formed, which after some time 

 collect on the surface of the fluid, and there run together to 

 form a thick, but dry skin ; the latter consists of very long 

 matted bundles and balls of pseudo-threads. There is no 

 formation of any gelatinous material. Fructification occurs 

 in the skin on the third or fourth day. The pieces of albumen 

 are not attacked to any marked degree by the growth of the 

 bacilli ; they retain their consistence and do not give rise to 

 any putrefactive odour. 



Bacillus Hansenii (Rasmussen). 



Motile rods 2'8 to 6 p. in length, and '6 to '8 /*. in breadth. 

 They form spores 17 /*. in length and 1*1 ^ in breadth. 

 They give rise to a whitish-yellow skin 011 meat infusion, 

 malt decoction, &c., at a temperature of 31 to 33 C. On 

 potatoes the growth is of a chrome-yellow colour ; at a later 

 period it becomes drier and orange-yellow, or yellowish-brown 

 in colour, and gives off a fruity odour. The pigment is in- 

 soluble in all the ordinary media (water, alcohol, chloroform, 

 lyes, acids). 



Bacillus tremulus. 



Shorter and thinner than bacillus subtilis, with a flagellum 

 at each end. It has a peculiar tremulous or rotatory movement. 

 The spore is thicker than the body of the bacillus, and it pro- 

 jects from the bacillus like a bladder; the completely formed 

 spore usually appears on one side of the rod. When the growth 



