THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[April 20, 1872. 
SI I 
the same amount of pepsin and hydrochloric acid, 
were made with that difference, that, while vial No. 
1 contained only 1 fluid ounce of water; No. 2 con¬ 
tained ^ drachm of alcohol and 7^ drachms of water; 
No. 3, 1 drachm of alcohol and 7 drachms of water ; 
and so each following vial drachm of alcohol 
more than the preceding one, so that in vial No. 
7 there were 5 drachms of water and 3 drachms of 
alcohol. The same amount of coagulated albumen 
was put into each vial, which was exposed then 
to a temperature of 100° F. After six hours in vial 
No. 1 all the albumen was dissolved; in No. 2 some 
albumen was left undissolved, No. 3 contained more, 
and in No. 4 over half of the albumen was not dis¬ 
solved, while in 5, 0, and 7 the albumen was a little 
changed in appearance, but the bulk not diminished. 
The contents of those vials in which the albumen 
was not much acted upon emitted that peculiar sour 
odour which characterizes discharges of an over¬ 
loaded stomach (with beer or wine) by vomiting. 
A solution of half a grain of purified pepsin in 
half a fluid ounce of water, with 3 drops of hydro¬ 
chloric acid, was mixed with 1 fluid ounce of 
sherry wine, after twenty-four hours filtered, and 
then, with the addition of 150 grs. of coagulated 
albumen, exposed to a temperature of 105° F. After 
six hours—during which time the half-grain of 
purified pepsin in acidulated watery solution would 
have dissolved 250 grs. of coagulated albumen—of the 
150 grs. at least two-tliirds yet remained. I added 
now (5 drops more of hydrochloric acid to bring the 
liquid to my standard acidity, but even at the end 
of twenty-four hours a large quantity of the albumen 
was undissolved. 
Having never made pepsin by any other method, 
I am not able nor justified to judge between the 
different products; but that my process excels by 
simplicity, nobody will question. That a compli¬ 
cated process, by which strong bodies, as mercury, 
lead and sulphuretted hydrogen, are alternately 
used to prepare a substance, should or might impair 
the quality of the product, is very probable. That 
pepsin, prepared by such a method, nevertheless 
lias the digestive power, speaks for the almost inex¬ 
haustible strength of it. 
Another point of importance in my preparation I 
would call attention to is that no artificial heat at 
all is used, neither by extracting the stomachs nor 
by drying the pepsin, and in my whole process no 
evaporation is necessaiy. To evaporate the solution 
of a substance, for which a few degrees difference in 
heat decide between life and death, is a very delicate 
operation, which is easily carried out for experi¬ 
mental purposes, but on a larger scale is almost 
impossible. 
My pepsin differs from the pepsin described in 
Gmelin’s ‘Handbook,’ principally by the latter being 
easily soluble in water, while mine, although very 
soluble in the moist state, loses its solubility almost 
entirely by exsiccation. 
The pepsin precipitate which, combined with 
pepton, I obtained from the pepton solution, is more 
identical with the pepsin described in Gmelin’s ‘ Hand¬ 
book’ (vol. viii. Zoochemie), as it is easily soluble 
after having become dry, is completely precipitated 
by alcohol, shows a more acid reaction, and its clear 
solution becomes more turbid by addition of hydro¬ 
chloric acid than the pure pepsin. 
To bring the pepsin into a finely divided state, I 
preferred the use of milk sugar to that of starch, the 
substance generally used for this purpose, particu¬ 
larly by the French manufacturers; reasoning that 
sugar, with its antiseptic properties, will contribute 
to the stability of it, while starch, particularly in the 
damp state, is very apt to get mouldy, and will then, 
as a necessary consequence, cause the decomposition 
of the pepsin. 
When first making the commercial pepsin, which 
I called saccharated pepsin, I aimed to make it of 
such strength that 1 gr. of the saccharated should 
correspond in its digestive power to one teaspoonful 
of the liquid pepsin {American Journal of Pharmacy, 
January, 1871); that it can be made of much greater 
power I have plainly shown by the before-mentioned 
results. 
As for the precise strength that will be best suited 
for the human stomach, that will have to be deter¬ 
mined by physiologists. According to Scliroeder, 
the normal gastric juice of man dissolves 24 per 
cent, of coagulated albumen ; five grains of saccha¬ 
rated pepsin, which in acidulated solution dissolve 
00 grs. of coagulated albumen in four to six hours, 
would correspond to half an ounce of human gastric 
juice. No doubt the beneficial effect of pepsin has 
its limits. Several grains of the purified pepsin, of 
which 1 gr. dissolves 500 grs. of albumen in six 
hours, might do more harm in the human stomach 
than good, and might even do positive injury. 
But, in this essajg I have given only facts based 
on chemical experiments; to make use of these facts 
for therapeutical and physiological purposes, I leave 
to physicians.— Amer. Journ. of Pharmacy. 
BISULPHITE OF MAGNESIA. 
ITS PREPARATION AND COMPOSITION. 
BY GEO. ARCHBOLD, D.SC. 
Though the salts of sulphurous acid are well 
known, yet much diversity of opinion exists as to 
their real composition, and Mr. Carteiglie truly re¬ 
marked that not many bisulphites have been care¬ 
fully analysed in a pure state. It is not my intention 
in this paper to refer to all these salts, but simply 
to the one which has already been the subject of 
discussion; namely, bisulphite of magnesia. If we pass 
a current of sulphurous anhydride through a mixture 
of magnesia carbonate and distilled water, until the 
mixture is perfectly clear and has an acid reaction, 
on being carefully concentrated, it yields crystals 
of bisulphite of magnesia, as it cools, in the form of 
depressed tetrahedrons, which on analysis give the 
chemical formula of Mg 2S0 3 6H 2 0. The salt tastes 
earthy and also slightly of sulphurous acid. On ex¬ 
posure to the air, the crystals slowly become opaque 
and change into sulphate ; they are soluble in twenty 
parts of distilled water at 15 - 5° C., more so in boiling 
water, but crystallize on cooling. In order to 
ascertain the real percentage of sulphurous anhydride 
in this salt, and see whether Jt was a bisulphite, 
I proceeded as follows :— 
I. 100 grs. of the crystals prepared as above was 
pulverized and mixed with four times its weight of 
potassic nitrate, and a small quantity of the nitrate 
further laid upon the mixed salts. The whole was 
gradually heated in a porcelain crucible until it 
began to fuse, the sulphurous acid thereby being 
transformed into sulphuric, under disengagement of 
nitrous acid. The mass when cooled was dissolved 
in distilled water, supersaturated with HC1, and the 
