THEOBALD SMITH AND DOROTHEA E. SMITH 23 



Of the cultures isolated from swine which failed to give the same 

 reaction as the true hog-cholera bacillus was a non-motile organism 

 isolated by Professor T. J. Burrill from the liver of a pig in 1897, 

 and described briefly by one of us^ in 1899. This strain could be 

 differentiated from the true hog-cholera bacillus only through the 

 absence of motility and a reduced virulence. Bacillus coli following 

 this produced only a large bubble of gas in lactose bouillon. 



Among the cultures tried which belong to the first group are Hog- 

 cholera Nebraska (1886), Massachusetts (1895), Maryland (1898), 

 Arkansas (1899), and Hog-cholera X, XI, XH, XIII, XIV, and XVI, 

 each from a different outbreak; also suipestifer Voldagsen, and the 

 non-gas-producing hog-cholera strain of M. Dorset. In several of 

 the above strains mutants had appeared in the stock cultures. One 

 of these produced a viscid growth, the other had lost the power of 

 gas production in lactose. All these acted alike in not restraining 

 gas production subsequently by Bacillus coli. 



Among the paratyphoid and enteriditis strains in the collection the 

 following came under the second group : paratyphoid strains recently 

 isolated from four calves and one fetus by one of us; paratyphoid 

 Strains 225, 232, 234, and 242; Schottmiiller A and B; paratyphoid 

 from a pigeon and a cow's brain, all received from other laboratories; 

 Rat-typhus I, III, IV, and V; Swine-typhus I, II, III, IV, and V, 

 Spermophile typhus I, Dog-typhus I, Guinea pig-tjrphus VII, VIII, 

 Mouse- typhus I, II, Bacillus enteriditis 47, 204, Gaertner (Krai and 

 Mt, Sinai), and swine enteriditis. The one exception noted thus far 

 was marked paratyphoid (Longcope) . Dr. TenBroeck^ had previously 

 examined this strain and found it culturally and serologically a hog- 

 cholera bacillus. Its virulence, however, towards rabbits is very low 

 as compared with true hog-cholera bacilli. 



One culture of human typhoid tried thus far inhibited gas produc- 

 tion and belongs therefore to the second group. A culture of para- 

 typhoid bacilli from man which Hirschfeld has denominated Group 

 C and which has been shown by TenBroeck* to belong culturally to 

 the paratyphoid and serologically to the hog-cholera group, but with 



3 Smith, T., Cenir. Bakt., Ite AbL, 1899, xxv, 241. 

 * TenBroeck, C, /. Exp. Med., 1920, xxxii, 33. 



