THE BACILLUS FOR SMALL ANIMALS 161 



large omentum ; often there is a fair-sized nodule on 

 the caecum. The last mentioned is frequently lobu- 

 lated (like a gland), and may be simply attached to the 

 intestine by a broad pedicle ; it may, however, be 

 embedded in the organ, involving the peritoneal coat. 



The liver is often somewhat fatty, and on micro- 

 scopical examination the condition of this organ and of 

 the spleen is more or less identical with that found 

 when the intravenous method of inoculation is used. 

 The distribution of the bacilli in these organs is very 

 similar ; they are present twenty-four hours after the 

 inoculation, and, as in the intravenous cases, may 

 persist for a month. The caseous nodules referred 

 to often contain enormous numbers of small acid-fast 

 bacilli, presumably Johne's bacilli ; but it has been 

 found impossible to recover them in pure culture, due, 

 no doubt, to their being dead. Sometimes the number 

 of bacilli is small, as in the intestinal nodule of the 

 rabbit inoculated intraperitoneally by the authors. 



Acid-fast bacilli have not been demonstrated in any 

 of the remaining organs, all of which appear to be 

 normal. 



The Subcutaneous Inoculation of Rabbits. — The sub- 

 cutaneous inoculation of Johne's bacillus into rabbits 

 produces a caseous abscess at the site of inoculation. 

 These abscesses persist for a great length of time, but 

 the most interesting feature is the resistance of the 

 bacilli to destruction in this situation ; they can be 

 found in large numbers many months after the inocu- 

 lation, and remain well stained and formed. 



If dead bacilli are inoculated in place of living they 

 show an equally marked resistance to destruction. 

 Up to the present time not a single acid-fast bacillus 

 has been found in any of the internal organs of these 

 animals after subcutaneous inoculation. 



II 



