244 A MANUAL OF BACTERIOLOGY 



duces, or, finally, according to its general effect on 

 the body. Thus phthisis or consumption, lupus, 

 caseous pneumonia, cheesy inflammation of the lungs, 

 consumption of the intestines, tabes mesenterica, 

 tubercular pleurisy, ceseous broncho-pneumonia, 

 scrofula, tubercular meningitis, etc., are all forms 

 of the same disease, which is produced by a 

 microbe Bacillus tuberculosis discovered by Pro- 

 fessor R Koch 1 in 1882. This bacillus lives in the 

 blood and tissues, and gives rise to tubercles, which 

 are small abnormal nodules of newly-formed tissue 

 studding the diseased organ or organs. Each 

 tubercle is made up of nucleated cells and tubercle 

 bacilli, the latter being located chiefly in the giant 

 cells. As the tubercles are continually being 

 thrown off from the diseased person or animal, 

 tuberculosis is an infectious disease. B. tuberculosis 

 attacks other animals besides man ; among these 

 may be mentioned cows, fowls, rodents, pigs, etc. 

 Although tuberculosis is essentially the result of 

 the action of Koch's bacillus, there are certain 

 factors which render man and animals liable to 

 contract the disease, and thereby receive the poison. 

 These factors are deficiency of oxygen by bad venti- 

 lation, foods (from tuberculous animals), certain 

 diseases, 2 starvation, inheritance, predisposition, etc. 

 The last-named factor may be acquired through the 

 system being of a lower standard than usual, or 

 may be inherited. 



1 Berliner Klin. Wochenschrift, Bd. xv. p. 221. 



2 Among the diseases which render man liable to contract 

 tuberculosis are syphilis, diabetes, measles, whooping-cough, etc. 



