OBSERVATIONS ON EXTRACTUM CARNIS (LIEBIG). 229 
this, Dr. Stenhouse, extending the experiments of Strecker to the various 
tanning materials, showed that while most of the gallotannates could be 
split up into gallic acid and glucose, onty one mimotannate, viz. the tannin 
of the willow, would undergo the transformation, and he considered this 
a fair proof of the distinction between the two tannins. More recently 
the labours of M. Kawalier and M. Knop have tended to show that tannic 
acid is not a glucoside, since M. Knop has been able to convert the whole 
of tannin into gallic acid, except a loss of 4 to 6 per cent., which con¬ 
sisted principally of ellagic acid ; and he considers that this shows dis¬ 
tinctly that tannin cannot be arranged in that class of bodies to which we 
refer salicine, amygdaline, oesculine, etc.; and Kawalier has proved that 
though tannin may be obtained free from the impurity which furnishes ellagic 
acid, it cannot be entirely purified from the second body, which furnishes 
sugar when decomposed, although the amount of this impurity may be so 
much reduced, that the quantity of sugar bears no relation whatever to the 
weight of tannin employed. 
However, whether tannin be a glucoside or not, the experiments of Dr. 
Stenhouse remain the same ; whatever may be the body, which, undergoing 
decomposition, produces glucose, that body is not present with mimotannic 
acid ; and though not necessarily constant with gallotannic acid, which shows 
a distinction of species, the rule is sufficient to strengthen the argument for 
separating the varieties of tannin into two genera. 
For my own part, I am anxiously looking forward to the time when tannic 
acid shall be artificially produced by synthetical means ; synthesis is now 
making such rapid progress, that the above is not at all an extravagant idea; 
gallic acid has been already so prepared. We shall then, possessing a tannin 
free from organic impurities, be enabled both to estimate its combining 
number for analytical purposes, and also to set at rest all doubts respect¬ 
ing its constitution. 
OBSERVATIONS ON EXTRACTUM CARNIS (LIEBIG). 
BY THOS. T. P. BRUCE WARREN, F.E.S. 
If an aqueous solution of extractum carnis be digested with a large quan¬ 
tity of rectified ether, there is found on the surface of the solution, after a 
shofit time, a substance which does not dissolve in the supernatant ether, and 
if mixed mechanically, by agitation, with the solution, again separates, oc¬ 
cupying the same position as before. 
I was led to this observation on examining extractum carnis for fatty and. 
gelatinous matters about four years ago, during which time the contents of 
the bottle have remained undisturbed. I convinced myself at the time of its 
not being e ither of a gelatinous or fatty character; and not being at the time 
acquainted with a substance of such an apparently intermediate relation, I 
thought it would be interesting to determine at a future time the properties 
which this substance possesses as compared with the already examined prin¬ 
ciples existing in extractum carnis, and to compare it with the proximate 
principles existing in animal tissues, and which are possible to exist in ex¬ 
tractum carnis. 
The ether was first carefully decanted, and the solution separated by fil¬ 
tration, the substance remaining on the filter was thoroughly washed with 
boiling water. 
On the surface of the solution it appeared as a jelly-like stratum, with 
