‘December 21, 1872.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
487 
and shuts, and rapid suction is set up; and it is thus 
easy to obtain a vacuum equivalent’to 0 - 7 metre of mer¬ 
cury. The, working of the apparatus is obviously akin 
to that of the hydraulic ram ; so easily and efficaciously 
does it exhaust, that it will doubtless take the place of 
the Bunsen filter-pump. It has the great advantage 
of portability over the older form, since it may be so 
constructed that it ban he transported to any position in 
the laboratory: it obviates the necessity of a fall of up¬ 
wards of 30 feet, and therefore requires no alteration in 
the existing arrangements of pipes and. fittings; and, 
lastly, its cost need not exceed a few shillings. 
There are a few disadvantages connected with the 
use of the caoutchouc valve above described. Owing 
to the gradual diminution of its elasticity by long-con¬ 
tinued working, its efficacy diminishes after a time; it 
not only then fails to bring about rapid exhaustion, but 
so soon as the conjunction of its edges ceases to be per¬ 
fect, it allows the water to flow back into the caoutchouc 
tube. To obviate these inconveniences another form of 
valve was devised. A hollow metal cone shaped like a 
funnel is soldered air-tight into the end of the side tube 
B (fig. 2). This cone is pierced near its apex with a 
number of holes, and into it is fitted a piece of unvul¬ 
canized sheet caoutchouc shaped like a filter. This is 
retained in its place by a small screw passing through 
the sheet caoutchouc and into the apex of the cone. 
By its elasticity the india-rubber sheet presses firmly 
against the sides of the cone, and effectually prevents 
the entrance of air or water from the tube A; but the 
slightest pressure from within B is sufficient to disturb 
the adhesion, and to allow of the ready transmission of 
air through the holes in the cone. This valve is of a 
more durable and permanent character than the original 
form, and permits of a more rapid exhaustion. In the 
modified form of the instrument a manometer M is 
fixed to B; this allows the degree of exhaustion to be 
immediately ascertained from the position of the mer¬ 
cury along the graduated scale. The rapidity of the 
pulsations in the caoutchouc tube W W may be regu¬ 
lated by the moveable arm T, which by means of a 
screw can be clamped in any desired position. The screw 
S serves to regulate the rapidity of the exhaustion, or, in 
cases of simple aspiration, the amount of air passing 
through the holes in the cone. S' is a clamping ar¬ 
rangement, by which the vacuum within the pump can 
be maintained without disturbing the screw S if it 
should be necessary suddenly to disconnect the caout¬ 
chouc tube D from the vessel to be exhausted. 
This brief account of the slight but serviceable modi¬ 
fications in the original instrument of M. Jongo is made 
with the object of introducing an exceedingly valuable 
piece of laboratory apparatus to a more extended notice 
than it has hitherto met with in this country. 
THE AMOUNT OF CAFFEINE CONTAINED IN 
COFFEE, AND ON ITS PHYSIOLOGICAL ACTION. 
BY HERMANN AUBERT. 
Although the quantity of caffeine contained in raw 
coffee is known, no attempt has ever been made to ascer¬ 
tain how much of the alkaloid is contained in a cup of 
coffee, and it is also uncertain whether the beans should 
be slightly or strongly roasted, and whether the ground 
coffee must be boiled to extract its active principles or 
• simple infusion is sufficient. By extracting the coffee 
with water, either by percolation or decoction, and eva¬ 
porating to a syrup, which is then treated from five to 
eight times with chloroform at nearly 60° till all the 
caffeine has been dissolved out, he obtains a larger 
quantity than previous experimenters. Raw beans of 
the yellow Java kind yielded 0-709-0*849 per cent, by 
this method, while they gave only 0 ‘474 by Garot’s method 
■of precipitation -with basic lead acetate. When much 
. roasted, coffee loses a certain quantity of caffeine, which 
sublimes, whereas it loses none by slight roasting. Not¬ 
withstanding this, tbe coffee made in the usual way by 
percolation from strongly roasted coffee contains rather 
more caffeine than that made from an equal weight of 
slightly roasted coffee, as the roasting renders it more 
easy to extract. 
When coffee is prepared in the usual domestic fashion 
by pouring six to ten times its weight of boiling water 
three or four times over ground coffee, nearly the whole 
of the caffeine is extracted, hardly one-fifth of it. re¬ 
maining in the grounds. The quantity of caffeine in a 
cup of coffee prepared from 16§ grams of coffee is about 
0T to 0T2 gram. A cup of tea prepared in the ordinary 
way from 5—6 grams of Pekoe tea contains also about 
0T to 0T2 grams of caffeine. Caffeine acts upon the 
spinal cord and causes tetanus in doses of 0-005 gram 
for a frog, injected subcutaneously ; for a rabbit, 0T20 
gram (injected into the jugular vein); for cats, 0-200, 
injected in the same way; and the same quantity for 
dogs. It has a peculiar action on the muscles. of frogs, 
especially when directly applied to them, causing them 
to become rigid and white, apparently from coagulation 
of the myosin. It does not exert this action on the 
muscles of mammalia. The tetanus is removed by arti¬ 
ficial respiration, and if this process is kept up for about 
a quarter of an hour, no recurrence of the tetanus. takes 
place, even though the respiration is then discontinued, 
showing that the caffeine is quickly eliminated or de¬ 
stroyed in the organism. Occasionally it produces a 
paralysis of the hind legs in rabbits, but the author is 
uncertain to what cause this is to be attributed. It 
quickens the heart and at the same time reduces the blood 
pressure. This effect he believes to be due to stimula¬ 
tion of the cardiac ganglia, combined with diminution of 
what he regards as cardiac tone , due to paralysis of the 
nerves passing from these ganglia to the muscular sub¬ 
stance. . 
The action of caffeine does not explain the stimulating 
and reviving action of coffee.— Jouni. Chan, bocletij. 
CLOSING OF THE DUBLIN EXHIBITION AND 
AWARDS OF THE JURIES. 
- The Dublin Exhibition was closed on the 30th of 
last month by the Lord Lieutenant and the Countess 
Spencer by a ceremonial of some hours duration. 
Mr. Lee, the manager, who some time since was con¬ 
nected with the Crystal Palace, London,, received at the 
hands of his Excellency the order of knighthood. . This 
exhibition, although more of a national one than inter¬ 
national, has been attended with a considerable amount 
of success. The real promoters of the undertaking were 
Sir Arthur and Mr. Cecil Guinness, and it is generally 
supposed from the success that has attended it that their 
munificence will not be taxed to any great extent. 
It was not originally intended to give medals, but a 
short time before the close, and at the request of some 
of the Executive, it was determined to change the 
original plan. The following. will be found to be the 
awards of the jurors in Section A (natural products, 
food, raw materials). The awards were only publicly 
announced on the 1st of December, and in the official 
list of the awards, there is no intimation given of what 
the medal is given for. It merely gives the name of the 
firm to whom the award has been given, but the iollow- 
ino- list will be found to be correct. The exhibitors, are 
divided into four sections or classes, but as the exhibitors 
in the three other sections would not interest the readers 
of the Pharmaceutical Journal, Section A alone is 
given. 
The Jurors in Section A were 
John Adair, Esq.; John Bagot, Esq.; Prof. Barker, 
College of Surgeons; Prof. Cameron, City analyst; 
Charles R. C. Tichborne, F.C.S., etc., Apothecaries Hall 
ef Ireland; Alderman Purdon, etc. 
