Fune 4, 1885] 
NATUR 
117 
Eocene period of North America (illustrated), by E. D. Cope. 
—On the Labrador Eskimo and their former range southward, 
by A. S. Packard. 
Rendiconti del Reale Istituto Lombardo, April 23.—Some 
formulas for the calculation of the momenta of inertia in plain 
polygons, by Prof. G. Bardellii—Some remarks on the functions 
which satisfy the differential equation A*« = 0, by Prof. Giulio 
Ascoli.—Note on the morphological distinction between the 
various homologous and analogous organs of the different orders 
in the animal kingdom, by E. L. Maggi.—On a generalisation 
of the involute properties of complete squares and quadrilateral 
figures, by Gino Loria.—On a method of plain representation 
for the descriptive geometry of ordinary space, by Prof. F. 
Aschieri.—On the discontinuities in the secondary derived forms 
of the potential functions of a surface, by Dr. Paolo Paci.-— 
Meteorological observations made in the Royal Brera Observa- 
tory, Milan, during the month of April. 
Rivista Scientifico-Industriale, April 15-30.—Remarks on the 
velocity of the wind in connection with Prof. Archibald’s ex- 
periments with Biram’s anemometers, by the Editor.—Variations 
in the electric resistance of solid and pure metallic wires, accord- 
ing to the temperature (continued), by Prof. Angelo Emo,— 
Description of a new steam generator based on the principle of 
vortex circulation, by Prof. Annibale Riccd.—Note on the 
Emiberiza intermedia discovered by Dr. Michaellis in Dalmatia ; 
is it a distinct species in this family of birds? by Dante Roster 
SOCIETIES AND ACADEMIES 
LONDON 
Royal Society, May 7.—‘‘ Contributions to the Chemistry 
of Chlorophyll. Part I.,” by Edward Schunck, F.R.S. 
The paper treats of the products formed by the action of acids 
on chlorophyll. All who have worked with chlorophyll are 
familiar with the peculiar effects produced in solutions of chloro- 
phyll by the action of acids. The colour is changed, and an 
absorption spectrum makes its appearance, which differs from 
that of chlorophyll. According to some, these changes are due 
to a simple modification of the chlorophyll, others consider they 
are caused by the formation of products of decomposition. The 
latter view seems the more probable. 
On passing a current of hydrochloric acid gas into an alcoholic 
solution of chlorophyll, a dark green, almost black, precipitate 
is formed at once. The greenish-yellow liquid contains sub- 
stances extracted along with chlorophyll by the alcohol, and not 
connected with the latter. The precipitate consists essentially of 
two colouring matters, phyllocyanin and phylloxanthin, bodies 
that had been previously observed and so named by Fremy, who, 
however, did not obtain them in a state of purity. They are 
best separated by Fremy’s method, which consists in dissolving 
the mixture in ether, and then adding concentrated hydrochloric 
acid, when the liquid separates into two layers, a lower blue one 
containing phyllocyanin and an upper yellowish-green one 
containing phylloxanthin. It is immaterial what kind of leaves 
are taken for extraction, the products are always the same. 
The paper deals only with the properties of phyllocyanin, which 
are very peculiar. After being purified in the manner described, 
it is obtained as a dark blue mass resembling indigo, and con- 
sisting of microscopic crystals which are generally opaque, but 
Sometimes when very thin are translucent, and then appear 
olive-coloured. It stands heating to 160° without decomposi- 
tion, but between that temperature and 180° it is decomposed 
without previously fusing, leaving a charred mass which, on 
further heating, burms away without residue. It contains 
nitrogen, but is free from sulphur. 
Phyllocyanin is insoluble in water, petroleum ether, and ligroin, 
but dissolves in alcohol, ether, chloroform, glacial acetic acid, 
benzol, aniline, and carbon disulphide. The best solvent is 
chloroform. A minute quantity of the substance imparts an 
intense colour to any one of these solvents. It is only on 
_ diluting largely that the solutions lose their opacity. They then 
appear of a dull green or olive colour, and show the well-known 
and often described spectrum of so-called ‘‘acid chlorophyll,” 
consisting of five bands, three of which are very dark, one of 
_ moderate intensity, and the fifth very faint. 
By oxidising agents, such as nitric or chromic acid, phyllo- 
eyanin is easily decomposed, yielding yellow amorphous pro- 
ducts, the solutions of which show no absorption bands, It 
shows a remarkable degree of permanence as compared with 
chlorophyll, when exposed to the combined action of air and 
light, A chloroformic solution contained in a loosely-stoppered 
bottle may be exposed for weeks, or even months, to alternate 
sunlight and diffused daylight before its peculiar colour and all 
trace of absorption bands have disappeared. When the process 
is complete a yellow liquid results, which contains several 
products, all of them amorphous, one being easily soluble in 
water, and exceedingly bitter to the taste. The decoloration 
of a chlorophyll solution under the same circumstances would 
take place in a day or two. 
Phyllocyanin dissolves easily in concentrated sulphuric, hydro- 
chloric, and hydrobromic acids, yielding dark blue solutions, 
which show spectra differing from that of phyllocyanin, and no 
doubt contain compounds of the latter with acids, These com- 
pounds, however, are unstable ; for, on the addition of water to 
the solutions, phyllocyanin is precipitated unchanged. Phyllo- 
cyanin shows no tendency to combine with weaker acids, suchas 
phosphoric, oxalic, tartaric, or citric acid. 
Phyllocyanin dissolves easily in dilute caustic potash or soda 
lye. The solution gives precipitates of various shades of green 
with earthy and metallic salts, such as barium chloride, calcium 
chloride, lead acetate, and cupric acetate, and these might be 
called phyllocyanates. It seems, however, that by mere solution 
in alkali, phyllocyanin undergoes some change, for if acetic 
acid in excess be added to the solution, and it be then shaken up 
with ether, the precipitate dissolves in the ether, giving a solu 
tion which shows the bands of phyllocyanin ; but if the whole 
be Jeft to stand some time, the colour of the ethereal solution 
changes from green to brown, and it now shows a distinct and 
peculiar spectrum, characterised by two bands in the red and 
two fine but well-marked bands in the green, the third and fourth 
bands of phyllocyanin having disappeared, while the fifth still 
remains. The body yielding this spectrum has been prepared 
and found to yield microscopic crystals like phyllocyanin. A 
different product is formed when hot alkaline lye, or, what is 
better, boiling alcoholic potash or soda, isemployed. It crystall- 
ises in small rosettes, which are green by transmitted, of a fine 
purple by reflected, light. Its solutions have a dull purple colour, 
and exhibit a distinct spectrum characterised by a broad, very 
dark band in the green. It may be identical with one of the 
products obtained by Hoppe-Seyler from his chlorophyllan with 
alkalis. 
The concluding part of the paper treats of what may be called 
double compounds of phyllocyanin, into which metals and acids, 
especially organic acids, enter as constituents. Phyllocyanin 
seems to act the part of a weak base, uniting with strong acids 
and forming unstable compounds. In acetic acid it merely dis- 
solves without yielding any compound. In like manner, when 
freshly precipitated cupric oxide or zinc oxide is added to a soln- 
tion of phyllocyanin in boiling alcohol no combination takes 
place. A very different effect is observed when either of the 
two oxides is employed along with acetic acid. When cupric 
oxide is added to a solution of phyllocyanin in boiling acetic 
acid the solution acquires at once a deep greenish blue colour, 
and it no longer contains uncombined phyllocyanin, for its spec- 
trum is different, and, on standing, it deposits lustrous crystals, 
which doubtless consist of a compound containing phyllocyanir, 
acetic acid, and copper. If zinc oxide be employed, a similar 
effect is observed: the liquid acquires an intense green colour 
like that of a chlorophyll solution, and now contains the corre- 
sponding acetate of phyllocyanin and zinc. The same phenc- 
menon is seen when ferrous oxide, manganese oxide, or silver 
oxide is taken, liquids of various shades of green being obtained 
which contain phyllocyanin compounds ; but no similar cot- 
pounds are formed when potassium, sodium, barium, ca’cium, 
magnesium, or lead acetate is employed. Acetic acid is, how- 
ever, not the only acid which yields the reaction. If palmitic, 
stearic, oleic, tartaric, citric, malic, or phosphoric acid le em- 
ployed, it takes place just as with acetic acid, but in some cases 
time is required for its completion. Oxalic acid, however, 
seems to be without effect, and tartaric acid fails in some cases. 
The behaviour of phyllocyanin towards zinc oxide in the 
presence of acids may serve to explain a peculiar phenomenon 
first observed by Prof. Church, and subsequently described by 
Tschirch. The former took chlorophyll that had become brown 
on standing, and, acting on it with zinc powder, obtained a body 
yielding green solutions, which he took to be regenerated 
chlorophyll. Tschirch acted on Hoppe-Seyler’s chlorophyllan 
with zinc powder and observed the same phenomena, the con- 
clusion at which he arrived being the same, viz. that chlorophyll 
