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 Béchamp 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 Guérin’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 
