CHAPTER XXIX 

 TUBERCULOSIS 



Bacillus Tuberculosis (Koch) 



General Characteristics. — A non-motile, non-flagellate, non-sporogenous, non- 

 liquefying, non-chromogenic, non-aerogenic, distinctly aerobic, acid-proof, 

 purely parasitic, highly pathogenic organism, staining by special methods and by 

 Gram's method. Commonly occurring in the form of slender, slightly curved 

 rods with rounded ends, not infrequently showing branches, hence probably not a 

 bacillus, but an organism belonging to the higher bacteria. It does not produce 

 indol or acidulate or coagulate milk. 



Tuberculosis is one of the most destructive and, unfortunately, 

 one of the most common diseases. It is no respecter of persons, 

 but affects alike the young and old, the rich and poor, the male and 

 female, the enlightened and savage, the human being and the 

 lower animals. It is the most common cause of death among human 

 beings, and is common among animals, occurring with great fre- 

 quency among cattle, less frequently among goats and hogs, and 

 sometimes, though rarely, among sheep, horses, dogs, and cats. 



Wild animals under natural conditions seem to escape the dis- 

 ease, but when caged and kept in zoologic gardens, even the most 

 resistant of them — lions, tigers, etc. — are said at times to succumb 

 to it, while it is the most common cause of death among captive 

 monkeys. 



The disease is not limited to mammals, but occurs in a some- 

 what modified form in birds, and it is said even at times to affect 

 reptiles, batrachians and fishes. 



The disease has been recognized for centuries; and though, 

 before the advent of the microscope, it was not always clearly 

 differentiated from cancer, it has not only left unmistakable signs 

 of its existence in the early literature of medicine, but has also im- 

 printed itself upon the statute-books of some countries, as the 

 kingdom of Naples, where its ravages were great and the means 

 taken for its prevention radical. 



Spjecific Organism. — Although the acute men of the early days 

 of pathology clearly saw that the time must come when the parasitic 

 nature of tuberculosis would be proved, and Klebs, Villemin, and 

 Cohnheim were "within an ace" of its discovery, and Baumgarten* 

 probably saw it in tissues cleared with lye, it remained for Robert 

 Kochf to demonstrate and isolate the Bacillus tuberculosis, the 

 specific cause of the disease, and to write so accurate a description 



* "Virchow's Archives," Bd. ixxxil, p. 397. 

 t "Berliner klin. Wochenschrift," 1882, 15. 

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