3l6 MANUAL OF BACTERIOLOGY. 



tery, as it occurs in man, has been reproduced. Most labor- 

 atory animals are, however, very sensitive to the injection into 

 the tissues or veins of cultures, Uving or dead. They show the 

 lesions produced by various toxins. 



The bacillus is agglutinated by the patient's blood, but 

 often only late in the disease and apparently not in all cases. 

 This test seems to have only a hmited value in cUnical diag- 

 nosis. Many prefer to secure the reaction in a test-tube. 

 The dilutions used vary greatly (from i in 20 to i in 100 1. 



Fig. 95. — Spirillum: of Cholera (X 1000.) 



Immunized animals develop the agglutinins in the blood. 

 Results of experiment made for the production of a curative 

 serum are encouraging. 



It now seems that the bacillus of Shiga has numerous close 

 congeners, constituting with it a "group." To what extent 

 the others of the group may be concerned in the causation 

 of diarrheal diseases or may occur in the normal intestine 

 is uncertain. According to W. H. Park, some of these form 

 indol and develop acid from mannite which the bacillus of 



