26 HISTORICAL INTRODUCTION 



of ringworm, is due to the fungus Tricliophyton tonsuraun. 

 Klencke, in 1843, produced generalized tuberculosis in a rab- 

 bit by injecting tuberculous material into a vein in the ear, 

 but did not carry his researches further. Liebert identified 

 the Peronospora infestans as the cause of one type of potato 

 rot in 1845. The skin disease pityriasis (tinea) versicolor 

 was shown to be due to the Microsporon furfur by Eichstedt- 

 in 1846. 



Pollender, in 1849, and Davaine and Rayer, in 1850, inde- 

 pendently observed small rod-like bodies in the blood of 

 sheep and cattle which had died of splenic fever (anthrax). 

 That Egyptian chlorosis, afterward identified with Old 

 World "hookworm disease," is caused by the Ankylosto- 

 mum duodenale was shown by Griesinger in 1851. In the 

 same year the Schistosomum hematobium was shown to be 

 the cause of the "Bilharzia disease" by Bilharz. Kiichen- 

 meister discovered the tapeworm, Tenia solium, in 1852, 

 Cohn, an infectious disease of flies due to a parasitic fungus 

 {Empusa muscm) in 1855, and Zenker the Trichinella spiralis 

 in trichinosis of pork ("measly pork") in 1860. The organ- 

 isms just mentioned are, of course, not bacteria, but these 

 discoveries proved conclusively that living things of one Jiind 

 or another, some large, most of them microscopic, could cause 

 disease in other organisms and stimulated the search for 

 other "living contagiums." In 1863 Davaine, already men- 

 tioned, showed that anthrax could be transmitted from 

 animal to animal by inoculation of blood, but only if the 

 blood contained the minute rods which he believed to be the 

 cause. In 1865 Villemin repeatedly caused tuberculosis in 

 rabbits by subcutaneous injection of tuberculous material 

 and showed that this disease must be infectious also. In 

 this same year Lord Lister introduced antiseptic methods 

 in surgery. He believed that wound infections were due 

 to microorganisms getting in from the air, the surgeon's 

 fingers, etc., and without proving this, he used carbolic acid 

 to kill these germs and prevent the infection. His pioneer 

 experiments made modern surgery possible. In this year 

 also, Pasteur was sent to investigate a disease, Pebrine, 

 which was destroying the silkworms in Southern France. 



