December 14, 1872.3 THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
463 
caused the albumen to turn red, but after some time, 
when stirred, it regained its primitive colour. These 
changes of colour occurred repeatedly after additions 
of iodine until at length the red colour remained per¬ 
sistent and mucilage of starch was coloured blue. 
When this point was attained the liquid was agitated, 
and, after standing ten or twelve hours, it again re¬ 
gained its original colour; it then no longer gave 
the reaction with starch, except under the influence 
of chlorine water or nitric acid containing hyponitric 
acid. Even these were not sufficient to set free some 
portion of the iodine, it being necessary to incinerate 
with potash in order to obtain it in the state of iodide 
of potash. Professor Guerri found afterwards that 
even during the evaporation of the albumen to dry¬ 
ness the iodine remained in combination, and that 
during the process some white flakes appeared, which 
separated upon standing, and redissolved in a very 
small quantity of potash. 
According to careful experiments of Professor 
Guerri, 100 parts of tills iodized albumen, that had 
been dried at G0°C., contained 3132 parts of iodine ; 
and 474 parts of solution of albumen of 3° Beaume 
density when so evaporated yielded 3P928 parts of 
iodized albumen, whilst 31928 parts of iodized albu¬ 
men contained 1 part of iodine. The iodized albu¬ 
men forms yellow transparent scales, soluble in 
water, with the exception of a few flakes which are 
not dissolved by acetic acid or phosphoric acid, but 
are dissolved by alkalies. The solution is precipi¬ 
tated by alcohol; is neutral, and gives no iodine re¬ 
action. 
In order to obtain a ferruginous preparation of 
the strength before mentioned, Professor Guerri dis¬ 
solved 18 parts of ferric citrate,—corresponding to 
five parts of ferric oxide,—in 474 pails of solution of 
albumen, 3° Baume density, previously iodized, and 
evaporated the solution at a temperature of 00° C. 
to dryness. This gave 50 parts of a compound con¬ 
taining one-third of ferric citrate and two-thirds of 
iodized albumen. .The product so obtained has the 
appearance of ferric citrate, but is a little yellower. 
The solution comports itself similarly to the iodized 
albumen. The iron is not separated from it by 
alkalies, or by ferrocyanide of potassium, but is 
separated by the alkaline sulphides. 
Each of these preparations is easily formed into a 
pill mass with simple syrup, as well as with extracts 
not containing much tannic acid. They can also be 
administered in powder. 
THE CHEMICAL PROPERTIES OF 
EUCALYPTUS LEAVES. 
BY M. EABUTEAU. 
Iii a note presented at a recent session of the 
French Academy* M. Rabuteau describes the result 
of an attempt to ascertain whether the leaves of the 
Eucalyptus globulus, now frequently employed in 
cases of intermittent fever, contained any basic prin¬ 
ciple analogous to the alkaloids of quinine. 
Brunei, in a memoir upon the effects of eucalyp¬ 
tus, speaks of an undefined substance obtained from 
it which he calls eucalyptine; and in Corsica the 
medical men have administered, with success, a 
saline residue, obtained by treating an alcoholic ex- 
* ‘ Comptes Rendus,’ lxxv. 1032. 
tract of eucalyptus bark with sulphuric acid. If, 
however, the eucalyptus had contained a febrifuge 
alkaloid, M. Rabuteau thinks it would scarcely have 
escaped M. Cloez in his researches on eucalyptus 
leaves and eucalyptol; and a direct search for such 
an alkaloid by M. Rabuteau has led him to the con¬ 
clusion that one does not exist in the leaves. 
Having evaporated some alcoholic tincture of the 
leaves to half its original volume, the addition of 
water caused a plentiful precipitation of yellowish 
resin, which blackened upon exposure to the air. A 
few drops of hydrochloric acid considerably favoured 
the separation of this resin, which was soluble in al¬ 
kalies, and formed with them resinates. The slight 
alkalinity of the saliva was sufficient to dissolve it, 
with extreme slowness, but in appreciable quantity. 
A preparation might therefore be made from it ana¬ 
logous to certain medicinal tars, soluble upon the 
addition of an alkali. 
The liquor, separated from the resin and filtered, 
contained tannin, which imparted astringency to it, 
and was removed by a salt of iron. It was then 
treated with a solution of iodine in iodide of potas¬ 
sium, to precipitate an alkaloid if present; also with 
phospliomolybdic acid, but without success, although 
the latter reagent is said to be such a delicate test 
for an alkaloid that it gives a plentiful yellow pre¬ 
cipitate when caffeine is present in a solution in the 
proportion of lpart to 20,000, and a yellow turbidity 
with 1 part in 80,000. 
A decoction of powdered leaves of Eucalyptus glo¬ 
bulus, in water acidulated to separate all the resin, 
treated with the same reagents, yielded no trace of 
an alkaloid. 
CERTAIN UNDESCRIBED PROPERTIES OF THE 
CONCENTRATED SOLAR RAYS.* 
BY GEORGE ROBINSON, M.D., 
Fellow of the Royal College of Physicians of London. 
Some thirty years since, I accidentally noticed that 
the sun’s rays, concentrated by an ordinary lens and 
directed upon the hand immersed in water, produced im¬ 
mediate pain with burning heat and vesication. This 
experiment, varied and repeated at intervals on different 
living animal tissues and under different circumstances, 
always led to the same result. But if the concentrated 
rays were fixed for an instant upon the head of a small 
aquatic animal, death immediately resulted before vesi¬ 
cation occurred. On dead animal matters similarly 
treated, no perceptible effect was produced. 
The physiological action was, as I have stated, always 
instantaneous, but when a thermometer having a bulb 
of black glass was immersed in water, and the rays con¬ 
centrated on the bulb for some time, the instrument at 
the end of ten minutes only indicated a rise of tempera¬ 
ture from 60° to 80°. A few years since I happened to 
mention these observations to my venerated friend, the 
late Dr. John Davy, and at his request I prepared a short 
account of them, which he communicated to the British 
Association for the Advancement of Science, at its meet¬ 
ing in 1867. 
The rationale of the results witnessed in this simple 
experiment always seemed to me obscure, and to indicate 
the possible existence in the sun’s rays of some property 
or force that had not hitherto been investigated. Under 
this impression, and being myself engaged in practice, 
I took advantage of an opportunity to draw the atten¬ 
tion of the illustrious Faraday to this subject some 
fifteen years since, in the hope that he would apply his 
powerful mind to its elucidation. But in a kind letter 
* From the ‘ Scientific American.’ 
