366 L. A. KOHN AND C. KRUMWIEDE, JR. 



mable, and the containers are protected from leaking during 

 agitation in the machine only with difficulty. Two workers 

 abroad have developed typhoid fever while using the method 

 and we feel that there is a large element of danger in its use 

 because of the tendency for the contents of the bottles to blow 

 out when opened, due to the highly volatile pentane. 



CONCLUSIONS 



The petroleum-ether method for the detection of B. typhosus 

 has no advantage over direct plating on a medium which re- 

 strains the growth of the associated fecal types. With short 

 periods of exposure, it may be successful where direct plating on 

 Endo alone fails. There is a strong tendency to reduction of 

 the number of B. typhosus, not necessarily associated with a 

 greater reduction of the accompanying fecal bacteria. The 

 danger of infection to those using the method, however, is 

 sufficiently serious to warrant its condemnation, especially as it 

 offers no advantage over direct plating on differential restraining 

 media. 



REFERENCES 



BiERAST 1914 Centralbl. f. Bakt. Orig., 74, 348. 

 Hall, H. C. 1915 Bed. Klin. Woch., No. 52. 

 Jaffe 1915 Wien, Kl. Woch. No. 16, 418. 



Krumwiede, Pratt ANp McWilliams 1916 J. Inf. Dis., 18, 1. 

 ScHuscHA 1916 Centralbl. f. Bakt. Orig., 78, 226. Abstract in Bull. Inst. 

 Pasteur, May 15, 1917. 



