NON-SPORING BACILLI 279 



been called the bacillus of fish tuberculosis. It grows 

 luxuriantly at room temperature (20 C), and does not grow 

 at 37 C, its range being 15 to 30 C. It is non-pathogenic 

 for mammals, but kills frogs in a month. It shows some 

 degree of acid-fastness. 



Portals of Entry. Inheritance, ingestion, inhalation, 

 and inoculation. Cobbett recently traverses the theories 

 of Behring, Calmette, and Guerin, that the portal of entry 

 of the tubercle bacilli, even in the pulmonary form, is via 

 the alimentary tract and thence via the lymphatics to the 

 lungs. He concludes that the .intestine is not a common 

 port of entry for the tubercle bacilli which cause phthisis. 

 (Cobbett, " Portals of Entry of the Tubercle Bacillus," 

 Jour, of Path, and Bad., vol. xiv., No. 4, 1910, p. 563). 

 Leonard Findlay reaches the same conclusion from 

 experiments on the production of pulmonary anthracosis 

 in rabbits and guinea-pigs (Findlay, " The Origin of Pul- 

 monary Anthracosis, an Experimental Study." Zeitschrift 

 filr Kinder heilkunde, 1911, vol. ii., part 2 (June), p. 293. 

 B.M.J., 1911, vol. ii., p. 1278.) Feeding experiments 

 undertaken for the Royal Commission on Tuberculosis 

 gave results more in consonance with Calmette' s theories 

 (see resume on page 297 ; details in Appendix to Filial 

 Report, vol. i., pp. 48 and 52). 



Toxins. The tubercle bacillus secretes no soluble toxin 

 or only in very small amount. The chief toxic principles 

 are endotoxins or bacterial proteins. Dead bacilli will, if 

 inoculated in sufficient numbers, produce tubercle-like 

 nodules, in which giant cells and occasionally caseation are 

 present. These results are obtained with intravenous and 

 intraperitoneal injections, whereas subcutaneous injection 

 produces a sterile abscess (cold abscess). 



The hope of producing an active immunity led Koch to 

 employ various means to extract from dead and living 

 bacilli the complex bodies bound in them. 



1. Original Tuberculin, T.A. (Koch 1890-91). Tubercle 

 bacilli are grown in 5 per cent glycerin broth for six 

 to eight weeks. The entire culture is then heated on 

 the water-bath at 8o C. until reduced to one-tenth of 

 its original bulk. It is then filtered through sterile filter- 

 paper or through porcelain filters. The filtrate is a thick, 



