DESCRIPTION OF SI'K< II :>. 





FIG. 206. PURE-CULTURE OF BACILLUS 

 MEGATHERIUM IN GELATINE. 



Bacillus membranaceus ame- 

 thystinus (Eisenberg). Short rods 

 with rounded ends from 1 to 1-4 p. 

 long, and '5 to *8 p. broad. They 

 are grouped together irregularly. 

 Some individual bacilli stain more 

 deeply at the ends than in the 

 middle. Xon-motile. They grow 

 only between 15 and 20 C. Spore- 

 formation uncertain. 



The colonies gradually assume a 

 violet hue, and after liquefying the 

 gelatine float on the surface as violet 

 pellicles, resembling a membrane 

 stained with gentian violet. 



Inoculated in the depth of 

 gelatine a yellowish-white growth 

 appears on the free surface, which 

 after ten days or more becomes 

 violet. Liquefaction takes place 

 gradually, and in about a month 

 a thick violet layer covers the gela- 

 tine which lies beneath the liquid 

 part. 



On agar the growth, which at first 

 has a yellowish milky appearance, 

 becomes violet after eight or ten 

 days. In three or four weeks it 

 has become very much wrinkled, 

 and has a beautiful deep-violet 

 colour with a metallic lustre. The 



jelly is not stain,-,!, an.l the growth 

 can be easily removed from itH 

 surface. 



On potato they gn.w >l,,\vly, :m ,| 

 form a dirty yellow or olive-green 

 colour. 



In broth they grow very slo\ 

 after some weeks a violet d. : 

 and pellicle are formed, and tin- 

 liquid between becom.-.l.uk l.n.un. 



They were found in well water. 



Bacillus meningitidis puru- 



lentae (Neumann an.l Sehaflfer). 

 Rods 2 p. hi length. -0 to '1 p. in 

 width, and filaments. 



Colonies granular, greyish. 



In the depth of gelatine a gre\ 

 yellow filament develops, composed 

 of closely packed colonies, and on 

 the surface a greyish layer. 



On potato the growth is moist 

 and white. 



They are pyogenic in >mall ani- 

 mals and dogs. 



They were isolated from a case 

 of purulent meningitis. 



Bacillus mesentericus fuscus 

 (Fliigge). Rods small and short, 

 singly, in chains of two and i 

 Actively motile. Spore-formation 

 present. 



Colonies are at first roundish and 

 rather white, with a >hai|> outline : 

 later delicate brownish-yellow pro- 

 cesses appear. Liquefaction occurs 

 rapidly. 



Inoculated in the depth of gela- 

 tine a whitish growth forms along 

 the track of the needle, the upper 

 portion of which soon li<|ii< 

 greyish flakes float in the liquefied 

 portion. 



On pott wish 



growth appears on the first 

 but it soon becomes brown ami 

 wrinkled. It remains relatively 

 thin and -uprrii.-ial. ami quickly 

 spreads over the whole surface. 



They are foun-l 1.1 hay <lnst. in 

 the air. on tin- -in face of i>otai 

 anI an- v.-ry wid.-Iy -ii-ti iluted. 



Bacillus mesentericus ruber. 

 Sk-n.lcr rod in pairs, and 



in filaments. 



Colonies are rimii 

 Mi until they come t- th<- -nrface, 

 they produce a network and 



