BACILLUS TYPHOSUS. 419 



intracapillary "Widal reaction"? (See Widal Reac- 

 tion.) 



When the section is prepared for examination, if it be 

 gone over with a low-power objective, one will notice at 

 irregular intervals little masses that look in every respect 

 like particles of stain ing-matter which have been pre- 

 cipitated upon the section at that point. When these 

 masses are examined with a higher power objective they 

 will be found to consist of small ovals or short rods HO 

 closely packed that the individuals composing the clump 

 can often be seen only at the extreme periphery of the 

 mass. This is the characteristic appearance of the 

 typhoid organism in tissues, to which allusion has just 

 been made. The little masses are usually in the neigh- 

 borhood of a capillary. 



ISOLATION OF BACILLUS TYPHOSUS FROM CADA- 

 VERS. The spleen of a patient dead of typhoid fever is 

 the most reliable source from which to obtain cultures 

 of the typhoid bacillus for study. But it must always 

 be remembered that the same channels through which 

 the typhoid bacillus gains access to this viscus are like- 

 wise open to other organisms present in the intestines, 

 and for this reason bacillus coli, a normal inhabitant of 

 the colon, may also be found in this locality. 



RESULT OF INOCULATION INTO LOWER ANIMALS. 

 A great many experiments have been made in a variety 

 of ways with the view of reproducing the pathological 

 conditions of this disease, as seen in man, in the tis- 

 sues of lower animals, but with practically no success. 

 From the time of its discovery up to within a compara- 

 tively recent date there was an almost continuous con- 

 troversy concerning the infective properties of bacillus 

 typhosus for animals. By some it was held that the 



