814 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[April 12, 187?. 
Insoluble lead salts (in this case, the oleate and stearate 
of lead) are formed ; warm water is then added, and the 
aqueous liquid decanted, filtered, and sulphuretted hydro¬ 
gen passed through the filtrate, in order to precipitate a 
small quantity of plumbous oxide, which dissolves. The 
liquid is then digested with animal charcoal, and eva¬ 
porated in vacuo , or over a water-bath, until of the required 
specific gravity. 
(2) From the alkaline mother-liquor of the soap-works 
(from which the soap has been separated by means of 
common salt), by neutralizing with sulphuric acid, remov¬ 
ing the excess of that acid by carbonate of barium, eva¬ 
porating the filtrate to a syrup, digesting it for several 
days with alcohol, separating the alcoholic liquid from the 
sulphate of sodium, which crystallizes out, decolourizing 
with animal charcoal, again evaporating to a syrup, ex¬ 
hausting the residue with strong alcohol, and finally eva¬ 
porating the filtered solution over the water-bath. This 
process is, however, too troublesome and expensive for use 
on the large scale ; besides, it is found that, by adding 
great excess of alkali, the glycerine is taken up and the 
soap produced is found to absorb and hold a much larger 
percentage of water,—a desideratum to the manufacturer 
of cheap soaps. 
(3) From the residue of the manufacture of stearic 
acid for candles, by lime saponification. When this pro¬ 
cess is used, the glycerine remains dissolved in the water 
after the separation of the insoluble lime-soap. The lime 
also dissolved having been eliminated by either sulphuric 
acid, or, preferably, oxalic acid, the evaporation of the 
liquid to the consistency of a syrup will yield a glycerine 
pure enough for many technical purposes. This method, 
when properly carried out, yields a very pure product, and 
is the one principally used by continental manufacturers, 
but it is somewhat complicated, and unless great attention 
is paid to every part of it, small quantities of lime 
are apt to remain in the glycerine, rendering it unfit 
for use in medicine and pharmacy. 
(4) By decomposing or rather dissociating neutral fats 
by means of water, or of superheated steam. This is the 
best and only unobjectionable method of obtaining 
glycerine, and is the process brought to a successful issue 
by Mr. W. F. Wilson, F.R.S.* It consists in injecting 
superheated steam at a temperature of between 500 9 
and 600° into heated fat. The fats assimilate the ele¬ 
ments of water, and are decomposed into their consti¬ 
tuents—the fatty acids (oleic, stearic, or palmitic, as the 
case may be),—and glycerine ; both distil over and form 
in the recipient two layers of liquid, of which the lower 
is tolerably pure aqueous glycerine. Supposing palmatine 
to have been the material employed, 
G, H 5 ,3C, 6 H 81 0 2 + 3 H 2 O = C 3 H 5 ,3 H 0 + 3 H C 16 H 31 0 
Palmitine Water Glycerine Palmitic Acid 
First, we get a weak solution of glycerine containing 
from twenty to thirty per cent. ; then by concentration 
rough glycerine. Brown glycerine is the product of a first 
distillation—pale glycerine, white glycerine, produced by 
further distillation, show the successive stages of advance 
to pure glycerine. 
Properties. —Pure glycerine is a colourless, viscous, neu¬ 
tral, inodorous liquid, with a sweet taste, from whence it 
derives its name— y\vuvs, sweet. Concentrated as far as 
possible in vacuo over sulphuric acid, it has the sp. gr. 
1*28 at 59° (15°C). The glycerine of the British Phar¬ 
macopoeia has the sp. gr. 125, and contains five per cent, 
of water. Glycerine is difficultly volatile, and only begins 
to distil unchanged at 5183 Fahr. in a current of super¬ 
heated steam, or in a partial vacuum, but it cannot be 
distilled in the ordinary way without much decomposi¬ 
tion, intensely irritating vapours of acrolein being evolved. 
The vapour of glycerine is inflammable. Glycerine is un¬ 
cry stallizable ; at 408 Fahr. it becomes gummy and almost 
* We believe the originator of this method was Mr. 
Tilghman, of the United States.— Ed. Pharm. Journ. 
solid. It is miscible with water and alcohol in all propor¬ 
tions, and is a powerful solvent. Glycerine* is insoluble 
in ether, chloroform, etc. It does not evaporate, but on 
the other hand is hygroscopic, attracting moisture from 
the atmosphere and becoming more limpid ; like sugar, it 
possesses strong antiseptic powers. 
By gradually adding glycerine to a mixture of sulphuric 
and fuming nitric acids, carefully cooled, glonoin C 3 H 5 N 3 0 9 
(nitro-glycerine) is prepared ; on adding water to the solu¬ 
tion nitro-glycerine is precipitated as a heavy yellowish oil, 
soluble in alcohol and ether. It is a very unstable com¬ 
pound, and explodes when struck violently; it is largely 
used for various purposes, the preparation of dualine, and 
dynamite, etc. 
Glycerine treated with iodide of phosphorus, whereby 
iodide of allyl is formed on being dissolved in alcohol, and 
distilled wdth sulphocyanide of potassium, yields sulpho- 
cyan-allyl, or artificial oil of mustard. 
C 3 H 5 I + KNCS = KI-f(C 2 H 5 )N(CS)": 
Mustard Oil. 
or if sulphide of potash is substituted, sulphide of allyl 
(C 3 H 5 ) 2 S, essential oil of garlic is yielded. 
Various applications .—As may be imagined, glycerine 
being a production in which so many wonderful properties 
are combined, its applications and uses are now manifold, 
and it appears remarkable that whilst so many sources of 
impure glycerine have long been known to exist, hundreds 
of tons being thrown away annually, it is but of late years 
that it has been utilized, and now the demand for use in 
pharmacy, arts, etc., is with difficulty supplied. 
In the beginning of 1844 Mr. Thomas De La Rue, being 
engaged in some experiments requiring the use of syrupy 
substances, procured from the Apothecaries’ Hall, London, 
some glycerine, some of which he applied to a burn and an 
irritation of the skin. The experience thus obtained of its 
properties of soothing and keeping moist, led to its intro¬ 
duction into the Hospital for Skin Diseases, where it soon 
came into extensive use, and from this time it gained 
considerable favour with the medical profession, being even 
suggested as a substitute for cod liver oil, or at any rate a 
vehicle to render that medicine more palatable. But the 
question of purity arose, most of the samples at that time 
being found contaminated with lead, even in those samples 
which were sold as “pure and free from lead;” but since 
the introduction of Mr. Wilson’s process these contamina¬ 
tions need not be, and are rarely met with, so that now 
glycerine daily becomes more and more made use of in 
pharmacy and in the surgery. 
It must be borne in mind that in applying glycerine ex¬ 
ternally and internally it should be previously diluted. 
Glycerine has a strong affinity for moisture, it takes it 
from the skin and thus gives rise to a sense of burning. 
Dilution wdth water will mitigate this, and in most cases 
prevent it. In pharmaceutical preparations glycerine may 
be used as a preservative agent, and to economize the use 
of alcohol; its more important medicinal value is as a 
vehicle for the preparation of a great variety of remedies 
for both internal and external use. The therapeutic effects 
of some medicines are considerably modified by its use. 
Solutions in glycerine are practically found in the case of 
astringents to be much less active than solutions in water. 
Its usefulness as an application to the surface of the skin 
when dry and irritable, is testified by the fact that almost 
every pharmacist now-a-days has his speciality in the 
shape of glycerine lotion, glycerine cream, etc., and in the 
demand for the various manufactures of glycerine soaps. 
Mr. F. A. Sarg of Vienna claims to be the introducer of 
these things,d and he deserves praise for the perfection to 
which he has brought his glycerine toilet requisites; they 
really contain glycerine in very fair proportions. 
. * An interesting table of the solubility of various salts 
ln glycerine, by Klever, will be found in the first volume of 
the present series of the Pharmaceutical Journal. 
t Die Urtheile der ‘ Allgemeinen Weiner medizinischen 
Zeitung’ uber Glycerin. Jahrgange, 1869-70. 
