HISTORICAL. 15 



turned with a negative report as far as a bacterial cause of the disease was 

 concerned. In 1883 the German government sent a similar commission, 

 headed by Robert Koch, and the report of this commission was that Asiatic 

 cholera was caused by a bacillus, the famous comma bacillus of Koch. The 

 work of Koch in connection with the study of cholera seemed to act as a 

 wonderful stimulus, and other eminent investigators made important dis- 

 coveries within the year or two following. Klebs and Loffler discovered 

 the diphtheria bacillus in 1884. Fraenkel, Weichselbaum, and Friedlander 

 discovered the pneumococcus in 1884. Nicolaier and Kitasato discovered 

 the tetanus bacillus in 1884. Loffler and Schiitz discovered the glanders 

 bacillus in 1882, and the bacillus of hog erysipelas (Rothlauf) in 1885. 



Pasteur in 1881 made his first experiments in reproducing rabies in 

 susceptible animals by inoculation with material obtained from the spinal 

 cord, medulla oblongata, and lobes of the brain o animals dead from 

 rabies. In 1884 he reported his experiments pertaining to the modification 

 of the virulence of rabies by successive inoculations into susceptible animals. 

 His use of this modified rabies virus as a means of preventing a severe and 

 fatal course of the disease in those bitten by animals suffering from hydro- 

 phobia, is familiar to all. Thousands of cases have been treated successfully 

 at Pasteur institutes established throughout the larger cities of the civilized 

 world. 



The above are only a few of the important investigations of this period. 

 The causative relationship of microbes to certain diseases was undeniably 

 established. The voices of opposition were silenced. 



This period is especially nntahlp fpr the dpv^npmppt nf flntisppfir 



surgery. As a result, operations were no longer dreaded as in former times. 

 Fatal infections following operations now became rare. Thousands of lives 

 are saved. To remove or destroy the pus germs in open wounds or to pre- 

 vent the access of germs to wounds, cuts, and abrasions, has become a simple 

 matter, a simple mechanical application of suitable antiseptics. 



The progress of purely medical bacteriology was not so marked. Al- 

 though it was proven that certain diseases were due to bacteria, there were 

 no satisfactory means of destroying them in the system. Internal antiseptics 

 were tried, but without satisfactory results, as a rule. However, preventive 

 medicine based on a bacteriological knowledge gave good results. 



Period V. 



From Behring (1890) to Wright (1907). (Discovery of serum 

 therapy, bacterial vaccines, and development of utilitarian bac- 

 teriology.) 



The subject of immunity from disease received early attention. Age 



