34 STUDIES IN ADVANCED PHYSIOLOGY. 



BACTERIA. 



Very tiny living objects, visible only with the higher 

 power of the microscope, had frequently been observed by 

 botanists and zoologists. Their almost universal distribu- 

 tion had been commented upon. Attempts were made to 

 properly classify them in the system of nature. At first 

 regarded as animals, they have finally been relegated to the 

 domain of botanists, and are now viewed as belonging to 

 the plant kingdom. But little attention was paid to them 

 until the remarkable observation was made that there 

 seemed to be a causal connection between such micro- 

 organisms and certain known diseases. It is due to the 

 genius of the Frenchmen Davaine, Pasteur and Chauveau 

 to have given us the germ theory of disease, our notions of 

 fermentation, and the first successful attempts at pro- 

 tective inoculation, The first disease that was clearly 

 proved to be due to such organisms was the splenic fever, 

 which about the middle of this century was playing such 

 havoc with the sheep and cattle of the continent. Beyond 

 the peradventure of a doubt it was shown by these French- 

 men that these little germs not only caused the disease in 

 the animals studied, but that such germs might actually be 

 taken into the system of other animals, and so produce the 

 disease anew. 



A wonderful addition to our knowledge was made in 

 1872, when Klebs explained the phenomena of the inflam- 

 mation of wounds and blood poisoning. He had occasion 

 to examine numerous wounded soldiers of the Franco - 

 Prussian war, and observed that in the wounds and 

 abscesses of such individuals there were always found such 

 organisms, and he proved that even deeper portions of the 

 body to which the inflammation had extended had been so 

 diseased by the migration of these micro-organisms along 

 channels that he was able to trace. Few discoveries have 

 done so much to alleviate human suffering and to lessen 

 the dangers of surgical operations as this knowledge that 



