BACILLUS TYPHOSUS 513 



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 par- 

 ticles of staining-matter which have been precipitated 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 so closely packed that the indi- 

 viduals 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 neighborhood of a capillary. 



Isolation of Bacillus Typhosus from Cadavers. 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 likewise 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 tissues of lower animals, but 

 with practically no success. From the time of its discovery 

 up to within a comparatively recent date there was an almost 

 continuous controversy concerning the infective properties 

 of bacillus typhosus for animals. By some it was held that 

 the effects of its introduction into animals were manifestly 

 of toxic 1 origin,' while others regarded them as evidences of 



1 Toxic poisonous results not necessarily accompanied by the growth 

 of organisms throughout the tissues. 

 33 



