402 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [November 19,1870. 
enforce tlie advice to mount all starches for the mi¬ 
croscope “ dry ” and in “ dammar,” but by no means to 
place reliance upon shdes containing starch mounted 
in glycerine, camphor water, or fluids of any kind 
which maintain a condition of fluidity. 
THE PURGATIVE ACTION OF ALOES. 
BY T. AND H. SMITH. 
In the 19th number of the Pharmaceutical Jour¬ 
nal, there is published the report of a paper read by 
Mr. William Tilden, B.Sc., before the British Phar¬ 
maceutical Conference at Liverpool, entitled “A few 
Notes on Aloes.” In this paper Mr. Tilden gives 
some very valuable information concerning the che¬ 
mical properties of the drug, and we have much 
pleasure in bearing testimony to the ability of his 
researches, but, at the same tune, we feel called upon 
to notice one or two points in his paper, on which 
we conceive his deductions to be erroneous. 
He states that the active constituent of aloes is 
still unknown; that Robiquet first showed that the 
purgative property was not due to aloin; and he as¬ 
serts that this latter substance is in complete disuse. 
On these points we entertain entirely diverse 
opinions, and as the discoverers, and as far as we 
know the only manufacturers of aloin, we claim to 
some little knowledge of its chemical and therapeu¬ 
tical properties. 
Mr. Tilden enumerates and describes four sub¬ 
stances said to be present in aloes of the best quality, 
viz. :— 
(1.) Aloetin, aloesin, amorphous aloin, bitter prin¬ 
ciple of aloes. 
(2.) Crystallized aloin. 
(3.) Resin. 
(4.) Aloesic acid. 
Of these four Mr. Tilden disbelieves in the exist¬ 
ence of one, viz. aloesic acid, and adduces a reason 
why (3) resin should be related to the soluble portion 
of aloes. Of aloetin he remarks that it is very im¬ 
portant as to quantity, and there can be no doubt it 
is the product of the alteration of crystallized aloin. 
He regards it as a mixture of crystallized aloin, ca¬ 
pable of recovering its crystalline condition in pre¬ 
sence of water and brown oxidized matter. We have 
many and various reasons for at present coinciding 
to some extent with Mr. Tilden in these remarks, 
but we are entirely at a loss to imagine to what sub¬ 
stance he would attribute the purgative action of 
aloes, since he denies that aloin lias any such effect, 
and yet concludes that aloes absolutely consists of 
that substance and products of its decomposition. 
It is well known that the medicinal powers of 
aloes are not equal in different samples ; that of two 
samples of the same variety, one may possess twice 
the purgative action of the other, and that when the 
varieties are different, the difference in medicinal 
value is in many cases even more marked. 
. The idea of an active principle is generally tena¬ 
ciously associated with something such as strychnia 
or aconitia, of infinite power in small doses; but 
there are very many active principles, it must be re¬ 
membered, the powers of which are not very many 
times greater than those of the drugs from which 
they are obtained, and, in this present case, taking 
Mr. Tilden’s results, he could not possibly expect 
that aloin would have more than five times the power 
of good aloes, inasmuch as he obtains more than 
20 per cent, of the principle from the drug. 
If it be admitted that aloin is the active purgative 
principle of aloes, one manifest advantage from using 
it would be that we have therein a medicine of un¬ 
varying strength, and we possess what we judge to 
be conclusive evidence that there is no other sub¬ 
stance of value in aloes, and that in all cases where 
aloes of best quality will produce purgation, a pro¬ 
portionate dose of aloin will be of equal and more 
certain effect. 
When Robiquet, in 1856, published his research 
on Aloetin,* he denied that that substance (which 
he seems to have supposed identical w r ith aloin) had 
any purgative effect. At the time we contemplated 
publishing a denial of this, but the late Sir James 
Simpson happening to visit our works, we mentioned 
our intention to him, when he dissuaded us, observ¬ 
ing that medical men were quite sufficiently con¬ 
vinced of the power of aloin, and that he frequently 
prescribed it and often took it himself, and with un¬ 
varying good effect. We could name very many 
other medical men, of undoubted eminence, who con¬ 
stantly prescribe it in preference to aloes, finding 
that it has in no case any ill effect, and that there is 
never any need to give an increased dose when its 
use is regular and long continued. Our own per¬ 
sonal experiences bear out these statements, and our 
commercial transactions give most emphatic testi¬ 
mony that the demand is not decreasing. Since its 
first discovery, our manufacture has increased from 
a few pounds to many thousand ounces yearly, and, 
although we have not arrived at Mr. Tilden’s grati¬ 
fying result of 20 per cent., yet, b}- r recent improve¬ 
ments in our manufacture, we shall be able to pro¬ 
duce it at about two-thirds its present price, and we 
find the dose requisite to be aloin to aloes, as 1 is to 
5. We should be happy to forward that gentleman 
a few doses for purpose of trial, should he wish it. 
Edinburgh , November 12 th, 1870. 
for SMottfcs. 
CHEMICAL NOTES TO THE PHARMACOPOEIA. 
BY WILLIAM A. TILDEN, B.SC. LOND. 
DEMONSTRATOR OF PRACTICAL CHEMISTRY TO THE 
PHARMACEUTICAL SOCIETY. 
JEther. —Sulphuric acid and rectified spirit mixed 
together develope considerable heat, and if the mix¬ 
ture is distilled, ether is one of the products which 
find their way into the receiver. The process thus 
simply conducted, however, speedily comes to an end, 
so far as the production of ether is concerned. The 
plan adopted in the Pharmacopoeia is therefore that 
known as the continuous process. 
Sulphuric acid is mixed with rectified spirit, and 
the mixture heated to ebullition in a distillatory 
apparatus furnished with a good condenser; this is 
continually supplied with a stream of spirit [run in 
by a tube leading from a reservoir] at such a rate as 
to supply the place of that which undergoes etherifi¬ 
cation, and therefore distils over. The explanation 
usually given of this reaction Is somewhat as fol¬ 
lows :—the spirit and sulphuric acid give, by their 
mutual decomposition, water and an acid, the ethyl- 
sulpliuric, or sulphovinic. 
* Journal de Fharmacie , tome xxix. 
