BACILLUS TYPHOSUS. 425 



reaction and it is often necessary to try a great num- 

 ber from various sources we have adopted the plan of 

 daily transplanting the culture into fresh bouillon and 

 keeping it at a temperature rarely above 20 or 22 C. 

 The bacilli grown under these circumstances are usually 

 somewhat longer than when cultivated at higher tem- 

 perature, and they exhibit a regular, gliding motility 

 that renders it more easy to follow the individual cells 

 under the microscope than when they possess the usual 

 active, darting motion. 



In the group of cases examined by us by the dry- 

 blood method, including typhoid and other febrile con- 

 ditions, there is a discrepancy between the clinical and 

 the laboratory diagnosis in from 2 to 3 per cent, of the 

 cases examined. 



In the hands of all who have carefully employed 

 the Widal reaction for the diagnosis of typhoid fever 

 the results are reported to have been almost uniformly 

 satisfactory. In the great majority of cases the reaction 

 is, so far as experience indicates, specific i. e., a typical 

 reaction does not occur between typhoid serum or blood 

 and organisms other than the typhoid bacillus, nor be- 

 tween the typhoid bacillus and serums other than those 

 of typhoid fever. There are, however, confusing reac- 

 tions so-called pseudo-reactions in which more or 

 less clumping of the bacilli and a diminution of motion, 

 without complete cessation, are observed. These reac- 

 tions have been seen to occur with normal blood and 

 with blood from other febrile conditions. It is said by 

 Johnston and McTaggart 1 that they can be prevented 

 if cultures of just the proper degree of vitality are em- 



1 Johnston and McTaggart : Montreal Medical Journal, March, 1897. 



