438 TUBERCULOSIS AND ITS PREVENTION 



cular. People did not accept Villemin's findings. They still clung 

 to the idea of spontaneous generation of this and other diseases. 

 In fact, he was treated as a disturber of medical order and beliefs. 



Professor J. Cohnheim, 1839-1884, at Breslau, found that he 

 could give tuberculosis to rabbits by putting a bit of the tubercular 

 patient's diseased lung into the front chamber of a rabbit's eye. 

 Here he could watch the little island of tissue spread and do its 

 deadly work of building tubercles. 



Koch discovers the cause of tuberculosis. Robert Koch (1843- 

 1910) built on Cohnheim's work. As long as animals could be 

 inoculated with the disease, he could experiment with them. 

 At this time, probably, one out of every seven people was dying 

 of tuberculosis. Koch took tubercles from a man who had died 

 of tuberculosis and injected them into the eyes of guinea pigs and 

 rabbits. While he was waiting for them to develop signs of the 

 disease, he examined tissues of people who had died of tuberculosis. 

 No microorganisms showed. He stained the tissues with different 

 dyes, in order to see the germs. (As he worked, he kept dipping 

 his hands into bichloride of mercury, for Lister, the English sur- 

 geon, had demonstrated the importance of antiseptics in checking 

 infections.) Finally, Koch smeared some material from tubercles 

 of a tubercular person on a glass slide, dipped it in a certain dye, 

 and mounted it under his microscope. He saw slender rod-shaped 

 organisms very minute in size, about 15 ^ 00 of an inch long. 

 The last stain had been successful. 



In the meantime, the guinea pigs and rabbits, which he had in- 

 oculated became sick and died. He examined their bodies, and 

 found tubercles which he stained and examined microscopically. 

 In every case he found the always slender, curved rods. He ex- 

 amined the bodies of many people who had died of tuberculosis 

 and always found tubercles. . Then he injected (inoculated) tuber- 

 cles into guinea pigs, rabbits, dogs, cats, and many other animals. 

 Invariably all the animals inoculated with the tubercles died of 



