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VIT. 



STUDIES IN TUBERCULOSIS. 

 I.-II. 



By a. E. METTAM, B.Sc, M.E.C.V.S., M.R.I.A. 



Read January 14. Ordered for Publication January 30. 

 Published February 11, 1907. 



I. — Infection of Bovines by the Avian Tubercle Bacillus. 



It will be remembered that Koch, at the London Congress on Tubercu- 

 losis in 1901, gave as his opinion that the organism of tuberculosis of 

 man was different from that producing tuberculosis in bovines ; and 

 he further asserted that the organism found in the lesions of oxen 

 was not pathogenic for man. Since that time much has been done in 

 investigating these statements of Koch ; and though it would be rash 

 to say that every tubercle bacillus isolated from lesions of bovines is 

 capable of producing tuberculosis in man, still it would be equally 

 wrong to assert that tubercle bacilli obtained from bovines are in 

 every case innocuous. 



Eor years past it has been recognized that bacilli obtained from 

 mammals differ in their morphological and other characteristics from 

 those isolated from birds ; and it has been recognized that the avian 

 bacillus is not so pathogenic for mammals as for birds. Eurther, it is 

 maintained that mammalian tubercle bacilli are not so pathogenic for 

 birds as those of avian origin. As an experimental fact, we may 

 mention that the guinea-pig resists the avian tubercle bacillus, whilst 

 the rabbit responds, and rapidly so. On the other hand, tubercle 

 bacilli of mammalian origin rapidly cause wasting, lesions, and death 

 in the guinea-pig, but not so certainly in the rabbit. 



The tubercle bacillus of mammalian origin grows slowly upon the 

 ordinary laboratory media. The colonies are warty and rugose, dry 

 and scaly. The scales formed of myriads of organisms are broken 

 down with difficulty. 



The avian bacillus grows rapidly. The colonies are whitish, fatty 

 in appearance, moist, do not form scales, and the organisms can easily 

 be disassociated. 



R.I. A. PROC, VOL. XXVI., SECT. B.] JS^ 



