THE ACID-PROOF BACTERIA. 369 



characterized by proliferation of the fixed cells with 

 little evidence of leucocytic invasion ; later on, true 

 giant-cell formation is recorded by some observers. We 

 have not seen this. Clumps of endothelial nuclei or of 

 lymphoid cells that remotely suggest the arrangement 

 seen in giant cells are often encountered, but we have 

 not regarded them as true giant cells. When fully 

 developed, the nodule may present a mixed condition of 

 caseatioH and suppuration. The conditions, as a whole, 

 when advanced suggest a low grade of inflammatory 

 reaction. Occasionally nodules are encountered, espe- 

 cially in the kidney, that cannot be distinguished from 

 tubercles. The bacilli are always to be found within 

 the nodules ; most frequently as single rods or clumps 

 of rods, occasionally as rosette-like mycelia very sug- 

 gestive of the characteristic growth of the actinomyces 

 fungus in the tissues. This mode of development has 

 also been observed with bacillus tuberculosis. 



It is important to note the difference between the re- 

 sults of intravenous inoculation of rabbits with bacillus 

 tuberculosis and with the organisms under consideration. 

 When bacillus tuberculosis is employed, the lungs, as 

 well as the kidneys, are always involved, while with the 

 grass bacillus II., the timothy bacillus, and the butter 

 bacillus, involvement of the lungs, in our experiments, 

 has been the exception rather than the rule. 



Another point of interest is the lack of tendency on 

 the part of the non-tuberculous process to progress or 

 become disseminated. 



That the members of this group are botanically 

 related to bacillus tuberculosis there seems little room 

 to doubt ; but from personal study and from available 

 evidence from other sources it appears unlikely that 



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