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XXXII. On the Products of the Destructive Distillation of Animal Substances. 
Part I. By THomas AnpErson, Esq., M.D. 
(Read 3d April 1848.) 
In April 1846, I communicated to the Royal Society a paper on a new organic 
base, to which I gave the name of Picoline, and which occurs in coal-tar, asso- 
ciated with the Pyrrol, Kyanol, and Leukol of Runce. In that paper I pointed out 
that the properties of picoline resembled, in many respects, those of a base which 
UNVERDORBEN had previously extracted from DippeEt’s animal oil, and described 
under the name of Odorine; and more especially mentioned their solubility in 
water, and property of forming crystallisable salts with chloride of gold, as cha- 
racters in which these substances approximated very closely to one another. And 
further, I detailed a few experiments on the odorine of UNVERDORBEN extracted 
from Drerev’s oil, with the view of ascertaining whether or not they were ac- 
tually identical, but on too small a scale to admit of a definite solution of the 
question. 
These observations, coupled with the doubts which had been expressed by some 
chemists, and more especially by REIcHENBAcH, as to the existence of the bases 
described by UNVERDORBEN, induced me to take up the whole subject of the pro- 
ducts of the destructive distillation of animal substances, which has not yet been 
investigated in a manner suited to the requirements of modern chemistry. In 
fact, UNVERDORBEN is the only person who has examined them at all, and his 
experiments, contained in the 8th and 11th volumes of PocGEnporr’s Annalen, 
constitute the whole amount of our knowledge on the subject ; and his observa- 
tions, though valuable, and containing perhaps as much as could easily be deter- 
mined at the time he wrote, are crude and imperfect, when we come to compare 
them with those which the present state of the science demands. Since his time, 
the methods of investigation in organic chemistry have undergone an entire 
change: the simplifications of the process of organic analysis had not then been 
made, or at least had not come into daily use as the auxiliary of investigation, 
and UNVERDORBEN, who belonged to the old school, and contented himself with 
the observation of reactions only, was necessarily led, as I shall afterwards more 
particularly shew, to confound together substances, the reactions of which approxi- 
mate so ‘closely that it is impossible, or at least very difficult, to distinguish them 
by such means alone. The errors, however, lay with the method, and not with 
the observer ; for UNVERDORBEN’s experiments, so far as they go, I have found to 
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