144 SPECIAL BACTERIOLOGY 



stand from twelve to twenty-four hours at 34 C., as recommended by 

 Rabinowitsch, is unnecessary.) 



2. From the organic lesions of the guinea-pig that die or are killed 

 in four to six weeks cultures are instituted on, at the least, eight to ten 

 tubes of blood serum, and at the same time pieces of the organs are 

 inserted into the peritoneal cavities of two guinea-pigs and one rabbit. 



3. These latter animals are killed not later than four weeks, and from 

 any existing lesions blood serum cultures instituted. 



Conclusions. (1.) It has been observed that genuine Koch tubercle 

 bacilli are often present in butter. 



(2.) Acid-resisting forms of bacteria are also found in butter, which 

 cause disease processes in guinea-pigs. These changes were, however 

 in the above authors' experiments not such that they could not be dis- 

 tinguished from the changes produced by genuine tubercle bacilli. 



EQUINE TUBERCULOSIS. 



In the horse this disease manifests itself in two forms. 



1. The Abdominal Form, which seems to be the more frequent, is 

 characterised by confluent lesions in the spleen, sub-lumbar and 

 mesenteric glands (for section of same showing tubercle bacilli, see 

 Photomicrograph, Fig. 51), liver, and intestinal mucous membrane. 

 According to Nocard, infection seems to take place by way of the 

 alimentary canal. When the lungs are invaded as a sequel of the 

 abdominal form, the lesions appear of recent origin, and consist of 

 a diffuse infiltration of the interlobular connective tissue without 

 apparent tubercles, caverns, or centres of softening, which, according to 

 the above authority, accounts for the absence of cough and discharge or 

 expectoration, and the non-transmission of the disease to other horses 

 in the same stable. 



Nocard also states that in advanced cases an abundant polyuria, 

 lasting for several weeks, occurs. Koch's bacilli are extremely abundant 

 in the lesions, and of very great length. Nocard considers that the 

 bacillus of equine abdominal tuberculosis is more closely allied to the 

 bacillus of avian tuberculosis than to the bacillus of mammalian tuber- 

 culosis. 



2. The Thoracic Form. In this type the disease seems to originate 

 primarily in the lungs, because these organs and the bronchial glands 

 are most severely affected. A genuine acute miliary tuberculosis some- 

 times occurs ; at other times the parenchyma of the lungs is studded 

 with small abscesses with a fibrous capsule, enclosing pus that is very 

 rich in bacilli. Nocard claims that the distinction drawn between the 

 two types of equine tuberculosis, on clinical and pathological grounds, is 

 confirmed by the determination of the causal agent, for while the 



