430 BACTERIOLOGY. 



thrown light upon the distribution of the organism in 

 the body daring life, yet as a regular means of diag- 

 nosis it is to be discouraged, on account of the possible 

 danger to the patient. The results of the examination 

 of the blood and rose-spots of typhoid patients have 

 in the main proved unsatisfactory, though the investi- 

 gations of some of the later observers have given a 

 number of positive results from the blood. The exam- 

 ination of the urine and feces of typhoid patients has 

 more often given positive results than the blood, 

 and these positive results have become more fre- 

 quent and satisfactory as the methods for differentiating 

 the bacillus typhosus have grown more exact and re- 

 fined. 



There are at present several recently devised media 

 employed for the isolation and identification of the 

 typhoid bacillus, which are much better than any of 

 those formerly used. These are the Hiss, Capaldi, 

 and Eisner media. In the hands of trained bacteri- 

 ologists they give satisfactory results. 



THE Hiss MEDIA : l T/ieir Composition and Prepa- 

 ration. Two are used: one for the isolation of the 

 typhoid bacillus by plate culture, and one for the 

 differentiation of the typhoid bacillus from all other 

 forms in pure culture in tubes. 



The plating medium is composed of 10 grammes of 

 agar, 25 grammes of gelatin, 5 grammes of sodium 

 chloride, 5 grammes of Liebig's beef extract, 10 

 grammes of glucose, and 1000 c.c. of water. When 

 the agar is thoroughly melted the gelatin is added and 



1 This description is taken Irom an article by Dr. Philip Hanson Hiss, Jr., 

 " On a Method of Isolating and Identifying Bacillus Typhosus and Members 

 of the Colon Group in Semi-solid Culture Media," published in the Journal 

 of Experimental Medicine, 1897, vol. ii. No. 6. 



