On Vegetable and Animal Analysis . 58 
tube is passed through a brick to which it is fastened with 
clay, and which at the same time gives solidity to the ap- 
paratus : besides this, we must solder to the body of the 
stopcock a small hollow cylinder in which water is put, or 
rather ice. 
W e have thus all the necessary data for knowing the 
proportion of the principles of the vegetable substances 
we know how much of this substance has been burnt, 
since we have the weight of it to a demi-milligramme : we 
know how much oxygen is wanted to transform it into 
water and into carbonic acid, since the quantity of it is 
given by the difference which exists between that contain- 
ed in the hyper-oxygenated muriate and that contained in 
the gases : lastly, we know how much carbonic acid is 
formed, and we calculate how much water ought to be 
formed. 
By following the same order of analysis, we also suc- 
ceed in determining the proportion of the constituent prin- 
ciples of all the animal substances. But as these sub- 
stances contain azote, and as there would be a formation 
of nitrous acid gas, if we employed an excess of hyper- 
oxygenated muriate in order to burn them, we need only 
employ a quantity sufficient for reducing them completely 
into carbonic acid gas, oxy-carburetted hydrogen, and 
azote, of which we perform the analysis in the eudiometer 
with mercury by the common methods, and from which 
we may conclude exactly that of the animal substance it- 
self. 
The method in which we proceed to the analysis of vel 
gc table and animal substances being exactly known, we 
can tell what quantity of it we decompose without any 
fear of weakening the confidence which we ought to have 
in our results. This quantity rises at most to six deci- 
grammes : besides, if there was the smallest doubt as to 
their exactness, we could get rid of it upon recollecting 
