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mains in an infinitely divided state suspended in the liquid, 
and communicates a blueish colour to it. If, to this solution 
ammonia be very gradually added till saturation, the fluid 
again becomes colourless, because the resin is again re-dis- 
solved." 
" Nothing is easier than to demonstrate how the sulphuric 
or any other acid, facilitates the solution of the subsulphate. 
The concentrated acids alter the composition of resins, espe- 
cially when aided by heat, and convert them into artificial 
tannin, but, when they are diluted they dissolve it without 
alteration. Nevertheless, as is the case in the acid solutions 
of quinia, the solution is not complete; the molecules are 
simply in a state of great division." 
"Some bodies having a great affinity for hydrogen or oxygen 
and chlorine appear to dissolve this resinate of ammonia in a 
more marked manner; but it appears that in such case, the 
constitution of the alkaloid has undergone more or less change, 
and that it is really modified." 
This explanation, ingenious as it is, does not appear to us 
to be exempt from objections, and M. Andre himself admits 
this, for he says, " I am far from asserting that my opinion is 
not liable to objections, it is not even new; but my object, in 
this paper, has been rather to attract the attention of more ex- 
perienced chemists to these difficult points, than to attempt an 
explanation of them." 
In fact, in the above explanation, we cannot see, why, if 
the acids and ammonia dissolve this electro-negative resin so 
readily, a resin allied to those so thoroughly examined by M. 
Unwerdorben, and which performs the part of an acid as re- 
gards ammonia or its elements; why, when the proportions 
of acid and ammonia predominate, there is not a complete so- 
lution, in fact, either the fluid is opaline and blueish, or there 
is a precipitation of white flakes. Moreover, if quinia is a 
kind of salt, with a base of ammonia, why, when it is heated 
with acids or alkaline oxides, is there not a formation of an 
ammoniacal salt or a disengagement of ammonia. 
Although this view of quinia as a species of resinate of am- 
