120 Chemical Besearches upon Diseased Milk, 



stances whose minute nature is indetermined. In fact, it is not 

 sufficient to have determined by the microscope a difference 

 between the globules of a healthy fluid, and those of this 

 same fluid which has been mingled with pus, that we may 

 thereby be in a condition to supply the demonstration of 

 which we are speaking. For, until we have given a specific 

 character to the globules of pus, — until we have defined the 

 immediate principles which constitute it, and the characters 

 of these principles, — ^until we have defined all the substances 

 which may produce pus, — and the circumstances which, by act- 

 ing upon some of its principles, cause it to become putrid, it 

 will be impossible to solve with certainty the question which 

 we have proposed in general terms. To justify this conclu- 

 sion, we have only to state, that colostrum (an ingredient of 

 many milks for some time after parturition) has the property, 

 according to M. Donne, of thickening the milk of which it 

 forms a part, on the addition of ammonia, as much as pus it- 

 self. 



Article II. — Concerning the nature of those substances of the exter- 

 nal world which exert an influence over organized beings. 



The atmosphere has such a vast influence upon the exist- 

 ence of animals, that, in all times, mankind have been led to 

 suspect that it was the cause of many maladies which at once 

 attacked a great number of individuals. It was on account 

 of this opinion, that, at the time when oxygen and nitrogen 

 were discovered to be the essential elements of the atmo- 

 sphere, the name eudiometer was invented to designate the in- 

 struments intended for detecting the respective proportions 

 in which they existed, and, by extension, the presence of 

 bodies which might be accidentally mixed up with them. 

 Those researches, however, which have hitherto been made, 

 with the object of discovering in an atmosphere, where the 

 population has been struck with an epidemic disorder, some 

 matter which might be the cause of that malady, have had no 

 precise result ; either, as has been asserted, by the discovery 

 of some peculiar foreign matter ; or the very reverse, as has 

 been alleged, by no difi^erence between the air of this atmo- 



