440 THE TUBERCLE BACILLUS GROUP 



phenomena. As tubercle bacilli reach the body (and as they escape 

 from the body) they are surrounded by a protective envelope which 

 causes the organism to behave somewhat as an inert foreign body 

 until it finally settles down in some structure where it can grow. 

 The envelope is then slowly removed or modified by the action of 

 normal tissue fluids and growth commences. In this connection it is 

 interesting to note that young tubercle bacilli are frequently non- 

 acid-fast, 1 and that the tissues usually invaded by the bacilli lym- 

 phoid tissue and the lungs contain active lipase. 2 If this supposition 

 is correct, the tubercle bacillus may remain latent in the body until 

 the fatty capsule is removed or modified, perhaps by a fat-splitting 

 enzyme (lipase) ; then development takes place. It should be remarked 

 parenthetically that polymorphonuclear leukocytes which occasion- 

 ally engulf tubercle bacilli do not contain lipase; 3 these leukocytes 

 may transport the organisms to lymphoid tissue or other tissue where 

 eventually the bacilli escape, thus establishing new foci. Mono- 

 nuclear leukocytes appear to contain lipase, as do certain fixed phago- 

 cytic cells in the alveoli of the lungs. 



Lenk and Pollak 4 and Wiener 5 appear to have found active proteo- 

 lytic ferments in tuberculous exudates. Opie and Barker 6 have shown 

 that the mononuclear epithelioid cells contain an enzyme which digests 

 protein in a slightly acid medium; it is practically inert in an alkaline 

 medium. Jobling and Petersen 7 have found that the inhibition of 

 enzyme action in caseous tubercle foci is apparently due to unsaturated 

 fatty acids. Saturation of these acids with iodin causes an accelera- 

 tion of the activity of the ferments. 



The primary lesions usually tend to progress slowly. Secondary 

 invasion by tubercle bacilli through the lymph and bloodvessels 

 frequently occurs, causing tuberculous foci in various ducts and 

 glands of the body, as the bronchi, alveoli of the lungs, spleen, liver, 

 tubules of the kidney, and in the genito-urinary system, particularly 

 the epididymis and testicle of the male and the Fallopian tubes in the 

 female. The glandular organs are those most commonly infected, 

 and of these the lungs and lymph nodes are most frequently involved; 



1 Wolbach and Ernst, Jour. Med. Research, 1903, x, 313. 



2 Bradley, Jour. Biol. Chem., 1913, xiii, No. 4. Briscoe, Jour. Path, and Bact., 1907, 

 xii. Bartel and Neumann, Centralbl. f. Bakt., Orig., 1909, xlviii, 657. Zinsser and 

 Carey, Jour. Am. Med. Assn., 1912, Iviii, 692. 



3 Fiessinger and Marie, Compt. rend. Soc. Biol., 1909, Ixvii, 177. Bergell, Miinchen 

 med. Wchnschr., 1909, Ivi, 64. 



4 Deutsch. Arch. klin. Med., 1910, cix, 350. 5 Biochem. Ztschr., 1912, xli, 149. 

 6 Jour. Exp. Med., 1908, x, 645; 1909, xi, 686. 7 Ibid., 1914, xix, 383. 



