100 STUDY AND IDENTIFICATION OF BACTERIA 



During the first twenty-four to forty-eight hours there is a moderate 

 acid production by typhoid, so that the milk culture is less blue, while 

 with the B. faecalis alkaligenes the alkalinity is intensified from the start, 

 so that the blue color is deepened. 



2. The Gartner or hog cholera group. Besides organisms im- 

 portant for animals and probably at times for man, such as B. cholerae 

 suum and B. psittacosis and B. icteroides (interesting historically as 

 having been reported as the cause of yellow fever by Sanarelli), we have 

 two pathogens: i. B. enteritidis (Gartner's bacillus) and 2. B. para- 

 typhoid B. In this connection it may be stated that the present view 

 is that hog cholera is caused by an ultra-microscopic organism and not 

 by the B. cholerae suum. 



These organisms cannot be separated culturally, but only by im- 

 munity reactions. They do not turn litmus milk pink. They produce 

 gas in glucose bouillon, but not in lactose. They very powerfully re- 

 duce neutral red with the production of a yellowish fluorescence. They 

 do not coagulate milk. There is a transient acidity in the litmus milk, 

 but becoming shortly afterward alkaline, the lilac-blue color is intensi- 

 fied. Both organisms are motile. 



3. The Escherich or colon group. These turn litmus milk pink, 

 coagulate milk, reduce neutral red, and show varying degrees of motility. 

 The three groups of organisms just described are nonliquefiers of gela- 

 tin. Two intestinal organisms, the B. cloacae and the Proteus vulgaris, 

 differ in liquefying gelatin. 



Bacillus typhosus (Eberth, 1880; Gaffky, 1884). This organism 

 may be isolated from the stools, urine, and the blood of typhoid patients. 



At postmortem it can be best isolated from the spleen, but is also present in 

 Peyer's patches which have not ulcerated. When ulceration has occurred contami- 

 nation with B. coli. is almost sure. Cultures may be obtained from the liver also. 

 In sections made from spleen the Gram negative bacilli are apt to be decolorized. 

 Thionin, then blotting and clearing in oil or xylol, shows the clumps of bacilli lying 

 between the cells. 



Formerly it was supposed that by the differences in the thickness of the film of 

 a colony or by its varying shades of grayish-blue, we possessed data of importance in 

 differentiating typhoid from related organisms. 

 ? ;Th cj&ipmes look like grapevine leaves. 



GrOwth *;en.,pota>x>w,as A!S(? considered as affording information. At present, 

 the, biochemical reactions give us-uucrroation assisting in differentiation, and the 

 agghVci nation ' 'aijd bactpriolytic phenomena, the final diagnosis. The various 

 plating medfe/are corisiderecl Uftder- media for plating out faeces. 



Not only do we find ny'pcrplasi'a ef rftfe/endothelial cells in the lymphoid tissue 



