BACILLI OF THE COLON-TYPHOID-DYSENTERY GROUP 041 



In milk, there is coagulation and an acid reaction at first; later the 

 casein is redissolved by proteolysis. Blood serum is often liquefied, 

 but not by all races. 



A great many really dissimilar bacteria have been described under 

 the name of Proteus. The type of the group is the so-called Proteus 

 vulgaris (Hauser, 1885). Other organisms spoken of as proteus are the 

 Proteus mirabilis, which differs in slower gelatin liquefaction from 

 vulgaris, the Proteus Zenkeri, which does not liquefy gelatin, the Proteus 

 septicus, and the Bacillus Zopfi, a Gram-positive organism. A good 

 many of these were formerly classified as of Bacterium termo. Closely 

 related is the slow liquefying organism known as Bacillus cloacce, com- 

 mon in sewage. 



There is no group which so urgently requires study as this, since 

 organisms belonging here are so often found in the human body and 

 human excreta. In urine we have encountered a non-gelatin liquefying 

 Gram-negative bacillus belonging to this group which has given us 

 much trouble in identification. As far as we can establish any general 

 characteristics for the group at all, we may say that they are Gram- 

 negative, non-spore-bearing, motile bacilli, which on the surface of 

 gelatin plates show colonies characterized by spreading streamers, 

 most of which liquefy gelatin, a few of which, however, do not. All 

 of them ferment dextrose and saccharose with gas, but few of them 

 attack lactose. 



The pathogenic powers of proteus are slight. Large doses injected 

 into animals may give rise to localized abscesses. In man proteus 

 infections have been described in the bladder, in most cases, however, 

 together with some other microorganism. The Urobacillus lique- 

 faciens septicus described by Krogius was a variety of this group. 

 Epidemics 23 of meat poisoning have been attributed to the proteus 

 family by some observers. Thus Wesenberg 24 cultivated a proteus 

 from 25 putrid meat which had caused acute gastroenteritis in sixty- 

 three individuals. Similar epidemics have been reported by Silber- 

 schmidt, 25 Pfuhl, 26 and others. 



B. CLOACAE. This organism was first described by Jordan and is 

 one of the commonest of the sewage bacteria. It is closely related to 

 the Proteus organisms, but is less motile than they. It coagulates milk, 

 and liquefies gelatin, but its gelatin liquefaction is not as active as that 



X 8chniteler, Cent. f. Bakt., viii, 1890. 



24 Wesenberg, Zeit. f . Hyg., xxviii, 1898. 



25 Silberschmidt, Zeit. f. Hyg., xxx, 1899. 

 29 Pfuhl, Zeit. f. Hyg., xxxv, 1900. 



