1)74 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[June 1, 18'?. 
to content myself with an examination of the variety 
named. 
I have employed two processes in my examination; 
the first being- mainly that given in the British Phar¬ 
macopoeia for the preparation of citric acid from lemon 
juice. 
One gallon of juice, freshly expressed from fully ripe 
tomatoes, was heated to the boiling-point and strained. 
Keeping it at about 200° F., powdered chalk was added 
until effervescence ceased. After cooling, the precipitate 
was separated by straining and filtration, and mixed 
with two pints of water. To the mixture was gradually 
added three pints of water, mixed with four fluid ounces 
of sulphuric acid, some effervescence being produced, 
probably due to an excess of calcium carbonate. The 
mixture was boiled gently for half an hour, and filtered. 
The filtrate, after partial evaporation, was set aside to 
allow any calcium sulphate which might be present to 
crystallize. After standing twenty-four hours the liquid 
was decanted—there being a slight sediment, but no 
crystals—and evaporated until a slight film began to 
form on the surface, when it was again set aside. 
After standing about three weeks there was a consi¬ 
derable deposit of brown extractive matter, having a 
crystalline appearance, from numerous small crystals 
imbedded in it. As this extractive evidently retarded 
the formation of crystals, and being pressed for time, I 
continued the evaporation at a gentle heat, until the 
whole was reduced to the consistence of an extract, 
which I brought with me on my return to the college, 
for further examination. 
Upon resuming operations in the laboratory of the 
college, I first made a preliminary examination of a small 
portion of the mass, according to the method directed in 
Will’s tables, and found present citric, malic and oxalic 
acids. In order to isolate them, the mass was boiled 
with a sufficient quantity of water, and the solution 
filtered. A small quantity of inert matter was left un¬ 
dissolved. The filtrate was neutralized with calcium 
hydrate, and the precipitate separated by filtration, and 
reserved. 
The filtrate from this was evaporated and boiled until 
the calcium citrate was precipitated, which was then 
washed with hot water, on the filter, mixed with a small 
quantity of pure water, and decomposed by dilute sul¬ 
phuric acid ; the calcium sulphate was allowed to deposit, 
the liquid was filtered, concentrated and set aside. 
After three days a number of crystals were found de¬ 
posited, but mixed with some viscid colouring matter. 
The mother-liquor was decanted, and after concentra¬ 
tion was set aside for further crystallization. The 
first crystals were dissolved in a small quantity of 
distilled water, the solution filtered, concentrated, and 
set aside. After standing twenty-four hours no crystals 
had formed in either liquid. They were then mixed, 
concentrated and filtered. After standing about two 
weeks, a small quantity of crystals had formed. 
These were separated, and the mother-liquor again 
concentrated, when a very small product was obtained. 
Owing to press of other duties I did not purify the 
resulting crystals. The yield was, however, very slight, 
being probably ten grains from one gallon of fresh juice, 
equal to about nine pounds of fruit. 
To obtain the malic acid, the filtrate left after precipi¬ 
tation of calcium citrate by boiling was concentrated, 
and calcium malate was separated by the addition of 
alcohol. Allowing it to subside, it was separated by 
filtration, and the filtrate again treated with alcohol to 
separate any remaining malate. A small quantity was 
obtained, and after filtration it was mixed with the first 
product. This was then dissolved in a small quantity of 
hot water, the solution filtered, and, after partial evapo¬ 
ration, mixed with an equal bulk of alcohol, and the 
mixture treated with dilute sulphuric acid. 
The resulting calcium sulphate was separated after it 
had completely subsided, and the filtrate, containing 
malic acid in dilute alcoholic solution, was partially 
concentrated. After standing twenty-four hours, no 
crystals having appeared, it was further concentrated 
and set aside. 
After standing about tw'O weeks, I found it had de¬ 
posited a quantity of coloured inert matter. It was 
again partially evaporated and filtered, and in a few 
days a quantity of crystals were obtained. 
While engaged in purifying these with animal char¬ 
coal, the entire product was lost by the accidental break¬ 
ing of the capsule containing the solution, so that I was 
unable to ascertain the exact weight of the purified 
product. It was, however, larger than that of citric acid. 
To obtain the oxalic acid, the precipitate obtained by 
neutralizing the original solution with calcium hydrate 
was treated with hydrochloric acid, the solution diluted, 
filtered, and neutralized by ammonia, when calcium 
oxalate was precipitated. 
This was boiled with a solution of potassium carbonate 
for two hours, and filtered to separate calcium carbonate. 
The filtrate was then mixed with alcohol to just below 
the point of precipitation, and the mixture treated with 
dilute sulphuric acid. The potassium sulphate being in¬ 
soluble in alcohol, readily subsided, leaving oxalic acid 
in alcoholic solution. 
This was then partially evaporated and set aside. 
After standing several days, a deposit of colouring and 
extractive matter was formed. This was separated, 
and the solution further concentrated and treated with 
animal charcoal. 
After a few days I obtained a quantity of small crys¬ 
tals. These were dissolved in a small quantity of distilled 
water, and again treated with animal charcoal and re¬ 
crystallized. The yield was about equal to that of malic- 
acid. 
The second process was as follows: One gallon of' 
fresh juice was boiled down to the measure of two pints. 
This was set aside and occasionally observed. After it 
had been standing about two weeks I found no result 
except the formation of a considerable brown deposit of 
extractive. It was then mixed thoroughly, and evapo¬ 
rated at a gentle heat to about three fluid ounces. 
This was then operated on in essentially the same 
manner as the first, diluting the liquid, filtering and 
neutralizing with calcium hydrate, and then isolating 
the acids from their lime salts. 
The results were similar, the yield of malic acid being 
rather larger. It has been stated tartaric acid existed 
in tomatoes in small quantities. I failed to obtain it, 
but hope at some future time to continue an investigation 
of various small acid fruits, and repeat that of tomatoes- 
with better facilities. I infer from the results obtained 
that the acids exist uneombined in the fruit. 
It is evident, however, that tomatoes are not available 
as a source of either of the acids.— Amer. Journ. Phann . 
NEW DESCRIPTION OF VALVE FOR GLASS 
TUBES. 
Messrs. Kay Brothers, of Stockport, have 
invented a simple and effective contrivance which 
they propose to adapt to infants’ feeding-bottles 
for the purpose of preventing the return into- 
the bottle of food after it has once been 
drawn into the suction tube. In these bot¬ 
tles the suction tube consists, as may be seen 
in the woodcut, of a piece of ordinary glass- 
tubing, contracted at the bottom to fit the- 
rounded end of a small piece of glass, whicK 
freely passes up and down and acts as a valve. 
When suction is applied this valve is raised as 
far as the indentation in the tube, thus permit¬ 
ting the free ingress of the food to the tube ; upom 
the removal of the suction it falls, and blocking 
up the orifice, prevents the return of the food, and 
therefore the necessity of exhausting the air afresh^ 
