MEANS OF DEFENCE AGAINST MICROBES. 247 



In fact, direct experiments, made with a maximum 

 registering thermometer enclosed in the dough, shows 

 that the internal temperature of the loaf, that of the 

 crumb, rarely rises to 100. We know that this tem- 

 perature does not suffice to destroy most microbes, 

 still less their germs, for which a temperature of from 

 115 to 160 is necessary. 



In 1884, Bouvet, a chemist, and Preaubert, a pro- 

 fessor at the Lycee, were commissioned by the munici- 

 pality of Angers to make a microscopic examination of 

 numerous specimens of well-water used by bakers in 

 their trade in different parts of the town. The exami- 

 nation of deposits, either obtained spontaneously by 

 allowing the water to stand for twenty-four hours, or 

 by testing the water with osmic acid, in accordance 

 with Certes's process, almost invariably revealed the 

 presence not only of the ova of ascarides, but of 

 numerous microbes some of them harmless, like 

 Bacterium termo ; others doubtful, on account of their 

 forming chains like the micrococcus (two species of 

 different form), and resembling Micrococcus dipTithe- 

 ricus. Now, croup may be regarded as endemic at 

 Angers. In four wells out of the twenty-five ex- 

 amined these microbes were found in great numbers. 

 It must be noted that micrococci are not found in 

 strongly aerated water, but only in that of which 

 the organic deposit is abundant. 



Well-water must, therefore, be generally condemned, 

 both for drinking purposes and for the making of 



