278 BACTERIA PATHOGENIC TO MAN 



fever, only very rarely did the serum give a marked immediate reac- 

 tion in a 1 : 10 dilution. In the light of past experience, I believe a 

 typhoid or paratyphoid infection, though not a typical typhoid fever, 

 to have existed in these cases. These results have been confirmed by 

 others, the question of dilution having recently been made the subject of 

 elaborate investigations, with the view of determining, if possible, at 

 what dilution the typhoid serum would react while others would not. 

 Thus, Schultz reports that among 100 cases of non-typhoid febrile 

 diseases apparently positive results were obtained in 19 with dilutions 

 of 1:5, in 11 of these with 1:10, in 7 with 1:15, in 3 with 1 : 20, and in 

 1 a very faint reaction with 1:25; whereas, in as many cases of true 

 typhoid he never failed with dilutions of 1 : 50. In these experiments 

 it must be noted, however, that the time limit was from one to two 

 hours. A faint reaction with a 1 : 25 dilution with a time limit of two 

 hours indicates less agglutinating substance than an immediate com- 

 plete reaction with a 1 : 10 dilution. 



From an experience with the practical application of the serum test 

 for the diagnosis of typhoid fever extending over seven years, it may 

 be said that this method of diagnosis is simple and easy of performance 

 in the laboratory by an expert bacteriologist, but it is not to be recom- 

 mended for routine employment by practising physicians as a clinical 

 test unless they have had experience; that with the modifications as 

 now employed, and due regard to the avoidance of all possible sources 

 of error, it is as reliable a method as any other bacteriological test at 

 present in use; and that as such the Gruber-Widal test is an indis- 

 pensable, though not absolutely infallible, aid to the clinical diagnosis 

 of irregular or slightly marked typhoid fever. 



Isolation of Typhoid Bacilli from Suspected Feces, Urine, Blood, Water, 

 etc. In the bacteriological study of typhoid infection for diagnostic 

 and other purposes, attempts have been made to isolate the specific 

 bacilli from the blood, rose spots, sweat, urine, feces, and by spleen 

 puncture. Although the results obtained by puncture of the spleen 

 have been encouraging and have thrown light upon the distribution 

 of the organism in the body during 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 investigations of some of the later observers have given a large 

 percentage of positive results from the blood. The examination of the 

 urine and feces of typhoid patients has more often given positive 

 results than the blood, and these positive results have become more 

 frequent and satisfactory as the methods for differentiating the bacillus 

 typhosus have grown more exact and refined. 



Several media recently devised for the isolation and identification of 

 the typhoid bacillus are much better than any of those formerly used. 

 These are the Hiss, Capaldi, Conradi, Drigalski, and Eisner media. 

 In the hands of trained bacteriologists they give satisfactory results. 

 The first three suffice for all ordinary purposes. 



