THEIR MODE OF ACTION. m 



A piece of the rennet-stomach of a calf in a state of decompo- 

 sition occasions the elements of sugar to assume a different 

 arrangement. The sugar is converted into lactic acid without 

 the addition or loss of any element. One atom of sugar of 

 grapes C l2 H 12 O l2 yields two atoms of lactic acid = 2 (C 6 

 H. O, ). 



When the juice of onions or of beet-root is made to ferment at 

 high temperatures, lactic acid, mannite, and gum are formed. 

 Thus, according to the different states of the transposition of the 

 elements of the exciting body, the elements of the sugar arrange 

 themselves in different manners, that is, different products are 

 formed. 



The immediate contact of the decomposing substance with the 

 sugar is the cause by which its particles are made to assume new 

 forms and natures. The removal of that substance occasions 

 the cessation of the decomposition of the sugar, so that should 

 its transformation be completed before the sugar, the latter can 

 suffer no further change. 



In none of these processes of decomposition is the exciting 

 body reproduced ; for the conditions necessary to its reproduction 

 do not exist in the elements of the sugar. 



Just as yeast, putrefying flesh, and the stomach of a calf in a 

 state of decomposition, when introduced into solutions of sugar, 

 effect the transformation of this substance, without being them- 

 selves regenerated ; in the same manner, miasms and certain 

 contagious matters produce diseases in the human organism, by 

 communicating the state of decomposition, of which they them- 

 selves are the subject, to certain parts of the organism, without 

 themselves being reproduced in their peculiar form and nature 

 during the progress of the decomposition. 



The disease in this case is not contagious. 



But, when yeast is introduced into a mixed liquid containing 

 both sugar and gluten, such as wort, the act of decomposition of 

 the sugar effects a change in the form and nature of the gluten, 

 which is, in consequence, also subjected to transformation. As 

 lon_>; as some of the fermenting sugar remains, gluten continues 

 to be separated as yeast, and this new matter in its turn excites 

 fermentation in a fresh solution of sugar or wort. If the sugar, 



