26 NATURE 
{Marcu 4, 1915 

Linnean Society, February 18.—Prof. E. B. Poulton, 
president, in the chair.—Harold Wager: The action of 
light upon chlorophyll. By making a film of chloro- 
phyll upon paper and on glass, by floating an alcoholic 
solution, and allowing it to dry, the author was able 
to bleach a portion under strong sunlight, and cover- 
ing a portion by black paper; when this was tested 
by Schiff’s solution, the exposed, that is, the bleached 
portion, became pink, the unexposed portion showing 
no colour change. Another experiment was made by 
subjecting similarly bleached portions of chlorophyll 
to the action of potassium iodide, when the exposed 
parts turned reddish-blue, in consequence of the libera- 
tion of iodine, which acts upon the starch on the 
paper. The experiments clearly show that the decom- 
position of chlorophyll is accompanied by the forma- 
tion of an aldehyde and of something able to oxidise 
the potassium iodide and to set free the iodine. In- 
stead of alcoholic extract of chlorophyll we may use 
dried leaves, or chlorophyll expressed from leaves, or 
layers of Euglena or algze spread over the paper. The 
reactions also take place inside a leaf, if the bleaching 
has been efficient. Thus if sunlight is condensed by 
a lens upon a living leaf of Oxalis acetosella contain- 
ing plenty of starch, the chlorophyll is bleached in a 
small area, and if treated with Schiff’s solution, a 
strong aldehyde reaction results; if tested with 
potassium iodide the said area becomes blue. It 
having been stated that formaldehyde is produced when 
chlorophyll is exposed to sunlight in the presence of 
carbon dioxide, an attempt was made to determine 
whether such was the case in the present series of 
experiments, but the author was not able to satisfy 
himself on this point, though several of the tests suc- 
ceeded even with so small an amount as one-millionth 
of formaldehyde. Hydrogen peroxide had been sug- 
gested as the gaseous oxidising compound of chloro- 
phyll, but the result of many varied tests showed that 
this was not so. 
MANCHESTER, 
Literary and Philosophical Society, February 9.—Mr. 
F. Nicholson, president, in the chair.—Dr. T. Graham 
Brown: Note on the physiology of ‘‘ walking,’ with 
especial reference to its occurrence in the unborn 
foetus of the cat. The various reflexes have been 
examined in cat foetuses. The red nuclei seem to be 
capable of stimulation, and evoke their characteristic 
movements of the fore-limbs. The limb reflexes are 
very similar to those of the adult cat. The ipsilateral 
flexion-reflex and the contralateral extension-reflex 
have thus been observed. In the former reflex an 
extension rebound effect has been seen. Reflex in- 
hibition may be observed on pitting one reflex against 
another. If the foetus is shelled out of the uterus 
without delay into warm physiological salt solution it 
may be regarded as still unborn. In these circum- 
stances unmistakable movements of progression may 
be obtained on producing asphyxia by pressure upon 
the umbilical cord. They may sometimes appear to 
arise spontaneously. This observation shows that the 
mechanism for co-ordinate progression develops during 
intra-uterine life, and that the co-ordination of the 
mechanism is not conditioned after birth by a process 
of “learning.” The observation also shows that the 
rhythmic activity may be evoked by the general 
stimulus of asphyxiation before it has been evoked 
or conditioned by any rhythmic self-generated peri- 
pheral stimuli such as those which play an important 
part in normal progression, but have been shown not 
to be its intrinsic factors. It thus also gives another 
demonstration of the similarity between the respira- 
tory mechanism and that for progression.—Prof. G. 
Elliot Smith: The Darling Downs skull. Photo- 
graphs were shown of a completely mineralised 
NO. 2366, VOL. 95] 


human skull, which had been found near Warwicix 
in the. Darling Downs of Queensland, and was 
described by Profs. Edgeworth David and Wilson 
at the recent meeting of the British Association in 
Australia. This important discovery of the earliest 
human remains yet known in Australia seems to prove 
that Man reached Australia at a time when the great 
fossil marsupials were still living. 
Dupuy. 
Royal Dublin Society, February 23.—Prof. Wm. 
Brown in the chair.—Prof. Grenville A. J. Cole: The 
mode of occurrence and origin of the orbicular granite 
of Mullaghderg, Co. Don:gal. The structure and 
mineral characters of this rock were described by 
Dr. F. H. Hatch in 1888. A recent visit by the Geo- 
logical Survey has enabled large specimens to be 
procured, the surfaces of which have been - polished. 
The nucleus in several of the large spherulites is seen 
to be a flake of schistose rock. In most cases, how- 
ever, it consists of granite, somewhat poorer in biotite 
than the granite which includes the spherulitic bodies. 
The very local occurrence of this orbicular rock as a 
variation on the general red granite of the district 
leads to the conclusion that the spherulitic bodies 
represent inclusions from the roof of Dalradian schists 
which once overlay the granite cauldron. Such in- 
clusions may have fallen in from a cold portion of the 
roof and thus promoted a rapid crystallisation of 
oligoclase round about them by interaction of their 
constituents and those of the granite magma. Blocks 
of already cooled granite may have fallen back also 
from the roof of the dome, and may have supplied 
nuclei for spherulitic growth. The occurrence of 
granite round about schist-fragments, and surrounded 
by a zone of radial oligoclase, suggests, however, an 
interchange of material between the granite and the 
schists. Granitic material seems to have soaked in 
while more basic material moved outwards to form the 
radially crystalline zone. Experiments by Tenow and 
Benedicks and by Endell are referred to: but no ex- 
planation can be offered as to why orbicular structure 
is so rare a phenomenon. 
EDINBURGH. 
Royal Society, February 1.—Sir E. A. Schafer, vice-- 
president, in the chair.—Mrs. Rosalind Jones (née 
Crosse): Studies on periodicity in plant growth. 
Part ii. Correlation in root and shoot growth. In 
a former paper the fact of a four-days’ periodicity in 
plant growth had been established; and in the present 
continuation the subject was further investigated. It 
was found that artificial changes in environment as 
regards heating and illumination did not affect the 
periodicity, and that there was correlation in the root 
and shoot growths.—Dr. J. Dawson: The histology of 
disseminated Sclerosis. This investigation, which had 
been partly outlined by the late Dr. Alexander Bruce, 
was based on an extended pathological observation 
disseminated sclerosis. This investigation, which had 
been studied largely by the method of serial sections 
stained by modern neuro-histological technique; and 
complete sections through the cerebral hemispheres, or 
large portions of the central nervous system, had been 
used to elucidate the distribution of the patches. 
Although no complete interpretation of the subject 
could be given, or no uniform conception of the process 
offered, certain conclusions were formulated, of which 
the following may be noted. The process underlying 
disseminated sclerosis is a sub-acute disseminated 
encephalo-myelitis, which terminates in areas of actual 
and complete sclerosis. There is overwhelming evi- 
dence that the gréat majority of the areas arise on 
the basis of an evolution through a stage of fat 
granule cell formation. There is much to favour the 
