368 French National Institute. 
advocates that made these statements necessary ; but it was 
allowed that, with the precaution just mentioned, there was 
good reason to ‘believe vaccination would be highly benefi- 
cial to society, and merited the further investigation re- 
quired for secure practice. 
FRENCH NATIONAL INSTITUTE. 
{Continued from p. 275.] 
M. Berthollet has taken up the subject of affinities with 
2 perseverance worthy of its importance; and he has this 
year communicated to us a third course of his researches. 
He has shown that we may by means of compression 
combine with the three alkalis quantities of carbonic acid 
much greater than usual, and thereby form salts perfectly 
neuter, like all the other acids. 
It is to these complete combinations that he reserves the 
name of carbonate: to the ordinary combinations he gives 
the name of sub-carbonate ; and he shows that there are be- 
tween the one and the-other several intermediate combina- 
tions. 
It is the same with the earthy carbonates and several sorts 
of salts: the phosphate of soda, for instance, can crystallize 
both with excess of acid and excess of base. ) 
Indeed the partisans of the old doctrine suppose, that in 
these cases of variable proportions there is no combination, 
but the superabundant principle is simply interposed in the 
free state between the molecules of the two principles com- 
bined in the ordinary proportion. 
M. Berthollet says in answer, that if this was the case, 
sulphuric acid poured upon a sub-carbonate would at first , 
take up some free alkaline molecules, before attacking those 
which. are combined with carbonic acid. But this is not 
the case ; for the least drop of the first acid immediately 
produces the liberation of the second, that is to say, effer- 
vescence. The acidulated sulphate of soda effloresces in the 
air, 2. e. it there loses its water of crystallization ; which 
would not take place if the superabundant sulphuric acid — 
was present in the free state, because there is no substance. 
which more strongly attracts humidity than this acid. 
M. Ber- | 
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