306 BRIEF HISTORY OF BACTERIOLOGY UP TO 1881 



the first instance of an infectious disease of plants shown to 

 be due to a microscopic plant organism, though not a bacte- 

 rium in this case. 



Doubtless one reason why the work on glanders and grain 

 rust attracted little attention among the practitioners of 

 human medicine was owing to the prevalent belief in man's 

 complete separation from all lower forms of life. The 

 evolutionists had not yet paved the way for experimental 

 medicine. 



In 1822, Gaspard showed the poisonous nature of material 

 from infected wounds by injecting it into animals and caus- 

 ing their death. Tiedemann (1822) and Peacock (1828) 

 described ''little bodies" in the muscles of human cadavers 

 which Hilton (1832) considered to be parasitic in nature. 

 Paget (1835) showed that these bodies were round worms 

 and Owen (1835) described them more accurately and gave 

 the name Trichina spiralis to them. Leidy (1846) found 

 organisms in the muscles of hogs which he considered to be 

 the same as Owen's Trichina and paved the way for the 

 work of Zenker (1860) in showing the pathological relation 

 between the Trichina of pork and human Trichinosis. 

 Bearing on the "contagium vivum" theory was the redis- 

 covery of the ''itch mite" {Sarcoptes scahiei) by Renucci 

 (1834), an Italian medical student. This had been declared 

 several hundred years before, but had been lost sight of. 

 Chevreuil and Pasteur, in 1836, showed that putrefaction 

 did not occur in meat protected from contamination, and 

 suggested that wound infection probably resulted from 

 entrance of germs from without. Bassi, investigating a 

 disease of silkworms in Italy, demonstrated that a certain 

 mould-like fungus (Botrytis hassiana) was the cause in 1837. 

 This was the first instance of a microscopic vegetable organ- 

 ism proved to be capable of causing disease in an animal. 



Boehm, in 1838, observed minute organisms in the stools 

 of cholera patients and conjectured that they might have a 

 causal connection with the disease. Dubini, of Milan, in 

 1838 discovered the Ankylostoma duodenale, which later was 

 further described by Omodei in 1843 and shown to be the 

 cause of Egyptain chlorosis by Griesinger (1851). The 



