64 BACTERIA. 



but as he was afterwards unable to find this same infu- 

 sorian in the pus taken from other abscesses, and in putre- 

 fying material that had been exposed to air, he was led to 

 inquire whether it was really characteristic of syphilitic 

 contagion, and whether it played any part in the trans- 

 mission of syphilitic infection. Although he afterwards 

 retired from his first position he carried out a series of 

 most careful and ingenious experiments, through which he 

 was led to believe that very characteristic vibriones were 

 associated with the causation and transmission of syphilis, 

 and he thus opened up a series of most interesting questions, 

 the answers to which, though differing somewhat from those 

 given by Donne himself, were nevertheless destined ulti- 

 mately to be very much on the same lines as those that he 

 had laid down. 



It is interesting to notice that the monad forms which at the present 

 day are again coming prominently forward in connection with the produc- 

 tion of certain diseased conditions, were early recognized and described by 

 Donne, and that Rudolph Wagner also described a species of monad as 

 occurring in cancer of the lip. 



As was to be expected, however, the connection of micro- 

 organisms with fermentation was proved long before a 

 similar association was made out between micro-organisms 

 and disease, and in the same year that Donne published his 

 results, Cagniard-Latour and Schwann, who had been work- 

 ing independently, announced that the yeast cells (torula 

 cerevisiae), originally described by Leeuwenhoek, and which 

 were found to grow in grape juice and malt wort were to be 

 associated with fermentation that they were indeed the 

 cause of this process. 



For long, although the intimate connection between the 

 process of fermentation and specific infective diseases was 

 widely recognized, the efforts of most scientific observers 

 were directed towards the elucidation of the causes of fer- 

 mentation and putrefaction. It was, in fact, suggested that 

 cholera might be due to the action of some ferment-causing 

 organism, which might become lodged in and multiply in 

 the intestine. 



In 1837, moreover, Bassi described a kind of yeast fungus, 

 which he thought must be the cause of a miasmatic con- 

 tagious disease in silkworms. He found extremely minute 

 spores, on and within the bodies of the silkworms affected, 



