292 MICROBES, FERMENTS, AND MOULDS. 



their existence is prolonged far beyond that of the 

 organisms of which they temporarily formed part. 

 Thus the microzyma of chalk, which doubtless have 

 their source in the animal and vegetable tissues of 

 that epoch, are still living after a repose of many 

 thousand centuries, and may be transformed into 

 bacteria if supplied with the fitting nutritive liquid, 

 as Bechamp has demonstrated. 



This is undoubtedly a very attractive theory, 

 which would explain a larger number of facts than 

 the theories previously stated, yet it is impossible to 

 make it agree with some of these facts, while they 

 are readily explained by the parasitic theory. Such, 

 for example, are the phenomenon of putrefaction, and 

 the benefits of Lister's dressing, and of Gue'rin's pro- 

 tective method applied to wounds. 



Robin, in his theory of blastema, also stated that 

 putrefaction took place without the intervention of 

 any external agent. 



It is, however, now known that when dead bodies 

 are protected from air-germs, they do not putrefy, but 

 become mummies. Such is the case with the bodies 

 which have been preserved for many centuries in the 

 crypt of one of the churches in Bordeaux, and which, 

 without any antiseptic preparation, have gradually 

 passed into the state of mummies. Many underground 

 buildings and caverns, in which the air is dry and 

 the temperature invariable, present conditions favour- 

 able to such transformation, doubtless because this 



