CHEMI CAL Bows |
Nov. 30, 1877.

Variegated Leaves, 237
pounds, fresh white ivy leaves contained 1°29 per cent,
‘he green giving 3-27 per cent. Similarly, white holly
-eaves contained 1°75 per cent, and green holly 2:54 per
cent,
But the most remarkable differences in composition beiween
 white and green leaves were noticed on submitting
the ashes of the several plants to quantitative analysis.
The nature of the results may best be seen by the following
table ;—

THE CHEMICAL NEWS.

VoL. XXXVI. No. 940.

VARIEGATED LEAVES.

By A. H. CHURCH, M.A,
Royal Agricultural College, Cirencester.

Percentage Composition of Ash.
Maple. Holly, Ivy.
White. Green. White. Green. White. Green,
Potash .. .. 45705 12°61 2530 1622 47°20 19°91
Lime .. .. 10°89 39°93 2I'50 "4°43 12°92 48355
Magnesia .. 3°93 475 3°23 +43 111 104
Ferric oxide .. (7) (?) SX 1 262 231
Phosphorus
pentoxide .» 14'57 880 9'51 +3 1068 3°87

Tus question of * albication,” “albinism,” or the white
variegation of leaves, does not appear to have been yet
approached from the chemical side, In studying the composition,
 modes of occurrence, and physiological position
of the common colouring-matters of plants, I have been
working at albication, in the hope of acquiring information
concerning chlorophyll. My results so far seem to open
up a new path of inquiry. The experiments were begun
too late in the year, and under the serious disadvantage,
from which much of my phyto-chemical work here suffers,
of the absence of a greenhouse. Still, I have obtained
some striking results, which if confirmed by further analyses,
 and supported by the very obvious synthetical
experiments which they suggest, may throw much light,
and must throw some, upon the nature and production of
chlorophyll.
The experiments, of which I now propose to give an
abstra®, were performed with three plants having their
green leaves variegated with white patches, or else bearing
both white and green leaves. ‘The plants were—r, Acer
Negundo ; 2, Hedera helix; 3, Ilex aquifolium. The
microscopic appearances were not neglected, but are purposely
 not alluded to here. I shall designate the plants
simply as maple, ivy, and holly, respectively, in this com.
munication.
The maple leaves were from trees in the Agricultural
College Botanic Garden, and were gathered on Sept. 17.
The holly was obtained from Messrs. Jefferies’s nurseries
on Sept. 24. For the ivy I am indebted to Mr. Taylor, of
Cirencester, a number of plants being laid under contribution,
 the date of collection being October 4. In every
case I gathered the leaves myself, and without the intervention
 of knife or scissors, Weighed bottles received
the specimens, so that no moisture could be lost during
transit to the laboratory. It is scarcely necessary to say
that every precaution was taken to gather only such leaves
as could fitly be compared in age and condition of growth.
The water, the combustible or volatile matter, and the ash
were first of all determined. The results, translated into
percentages, are here arranged in a tabular form :—
Maple. Holly. Ivy.
ree man reer, oi Pon
White. Green. White. Green. White. Green.
Water .. .. 82:83 72°70 74°14 62:83 7888 6613
Organic matter 15°15 24°22 23'66 3541 1874 3163
Ash.. .. .. 202 308 220 247 238 224
The watery chara®er of the white leaves, and their
comparative poverty in combustible, or so-called “organic,”
constituents, is very marked. It may be said, speaking
broadly, that the fresh green leaves of all three plants
contained one-third more solid matter than the white
leaves. The mineral matter or ash, when not absolutely
more abundant in the white leaves, forms a larger part of
their dry matter.
The nitrogen in both ivy and holly was found more
abundant in the dry matter of the white leaves than in
that of the green; but the percentages of nitrogen found
in the fresh leaves of the two plants were such as to ren.
der further analyses necessary.
The matters soluble in ether were estimated in the dried
leaves of holly and ivy. Of these matters, including wax
or fat, resin, chlorophyll, and several other organic com:

Although the above figures will require some correction
 (owing to the carbon dioxide of the various ashes
10t having been deducted); and although several impor-:ant
 ash constituents, such as chlorine and sulphur tri.
oxide, have yet to be taken into account before a final
judgment can be formed, yet these percentages already
teach us a good deal. In the ash of all three plants there
is the same kind of difference between the white and
green parts. Inthe ashof the white parts potash abounds,
and in the ash of the green parts lime; while in the ash
of the white parts there is invariably a higher proportion
of phosphates than in that of the green. There is, however,
 no indication that the presence of chlorophyll in the
green parts involves a higher proportion of iron.” On the
whole, the composition of the ash, as of the organic part
of these plants, suggests a comparison of the white parts
with the younger and more active parts of ordinary plants,
while the green parts resemble the more mature organs.
At present, further deductions would be hazardous, but a
series of synthetical experiments on variegated plants is at
nce suggested by the foregoing analyses, and by the
observation that, in some calcareous soils, many variegated
plants quickly revert to their normal green condition. I
nope before long to report the results of growing variegated
plants in soils nearly destitute of lime, but abundantly
supplied with potash salts and phosphates.—Gardener's
Chronicle, p. 580, 1877.

WHY MILK SOURS%DURING THUNDER-STORMS.

By MALVERN W. ILES. Ph.D.

THERE have been various surmises with regard to thig
subject ; none, so far as we have been able to learn, have
been substantiated by experiments.
In order to see if milk really did sour during heavy
:ain and thunderstorms I made several observations which
proved to me that the opinion so commonly held by dairymen
 was not erroneous.
My experiments to arrive at the cause of the phenomena
 thus observed may be stated as follows :—I filled
an eudiometer tube (300 c.c.) with skimmed morning's
milk, then introduced 100 c.c. pure oxygen gas; then, by
the use of an ordinary battery and a small Ruhmkorff
toil, sparks of eledricity were made to pass through the
oxygen for five minutes. The current was then broken
‘he tube shaken up, and allowed to stand for five minutes.
The milk did not appear quite so opaque, and showed a
10ticeable acid rea@ion. On continuing the current for
ive minutes longer, making in all ten minutes, the milk
;urdled very perceptibly, and showed a decided acid
-eation. The contents of the tube, on standing for