MarcH 4, 1915] 
NATURE 
a5 

SOCIETIES AND ACADEMIES. 
LONDON. 
Royal Society, February 25.—Sir William Crookes, 
president, in the chair.—Prof. L. Hill and J. F. 
Twort: The effect of the depth of pulmonary ventila- 
tion on the oxygen in the venous blood of man.—J. 
Barcroft and Toyojiro Kato: The effect of functional 
activity upon the metabolism, blood flow, and exuda- 
tion in organs. The organ studies have been skeletal 
muscle and the submaxillary gland. (1) The oxygen 
used by these organs not only increases during their 
activity but outlasts it by some hours. The curve of 
oxidation usually shows two maxima, the first during 
the period of activity, the second much later. (2) 
water leaves the blood-vessels in much greater quan- 
tities during and after activity of the organs than 
before; a similar second maximum is sometimes seen 
in the case of the exudation. (3) In the case of muscle 
not all the exudation leaves the muscles as lymph. 
Of the right and left gastrocnemius muscles, the one 
which has been stimulated is heavier several hours 
after the stimulation, and of lower specific gravity 
than the unstimulated one. (4) The dilatation of the 
vessels of the organ outlasts the functional activity 
for two hours or more in the case of muscle which has 
been stimulated rhythmically for fifteen minutes. (5) 
The tenseness of the muscle caused by its distension 
with water would seem to be the physical basis of 
stiffness.—Miss D. Jordan Lloyd: The osmotic balance 
of skeletal muscle. In order to free the phenomena 
as far as possible from complications due to the forma- 
tion of diffusion columns, a very small flat muscle— 
the sterno-cutaneous of the frog—was used. The re- 
sults of experiments show that an oxygen-saturated 
muscle has an osmotic equivalent less than that of 
distilled water.—Dr. A. J. Ewart: The function of 
chlorophyll. Previous observations of the author have 
tended to support the theory that chlorophyll is a stage 
in photosynthesis. The present paper develops this 
idea further. By means of Wellstatter’s methods of 
extraction and separation, chlorophyll, carotin, and 
xanthophyll were obtained in the pure state and used 
for the experiments. The following conclusions were 
reached :—(r) No peroxides, organic or inorganic, are 
produced during the photo-oxidation of chlorophyll, 
xanthophyll, and carotin. The oxidising effect of 
these latter substances on potassium iodide when they 
are undergoing oxidation in the light is due to the 
fact that in the presence of abundant oxygen they can 
act as oxidases, not only to themselves, but also to 
substances with which they may be in contact, such 
as hydriodic acid, litmus, or guaiacum. (2) Chlorophyll 
and xanthophyll decompose during photo-oxidation 
into (a) solids, and (b) a gas. The solids are colourless, 
waxy substances and hexose sugars. The gas is 
formaldehyde gas. With dry films in dry air free from 
CO, relatively more formaldehyde is produced and 
less sugar. (3) Carbon dioxide combines with chloro- 
phyll, forming xanthophyll and a colourless waxy solid. 
The combination only takes place actively in the pre- 
sence of water, and is accelerated by sunlight.—A. 
Compton: The influence of the hydrogen ion concen- 
tration upon the optimum temperature of a ferment.— 
M. Back, K. M. Cogan, and A. E. Towers ; Functional 
cedema in frogs. If the gastrocnemius muscle of a 
frog be stimulated for fifteen minutes with forty induc- 
tion shocks per minute it becomes heavier than the 
other. The difference in weight may amount to up- 
wards of 20 per cent. of the weight of the muscle. 
The specific gravity falls correspondingly. This pheno- 
menon may be noticed from fifteen minutes after the 
stimulation ceases to six hours. After sixteen hours 
the cedema has passed off. 
NO. 2366, VOL. 95| 
Physical Society, February 12.—Dr. A. Russell, vice- 
president, in the chair.—A. Campbell Swinton : A gal- 
vanic cell which reverses its polarity when iHuminated. 
If two plates—one of zine and the other of tinned 
copper coated on one surface with selenium and 
varnished with enamel over the remainder of its 
surface—are immersed in tap-water, the electric 
current through a galvanometer connected to the 
plates shows that in the dark the zine is electro- 
positive to the selenium, while the result of light 
falling on the selenium is to increase the effect. If, 
however, instead of zinc, carbon or copper is employed 
for the non-coated plate, the interesting result is 
obtained that, while the selenium proves to be electro- 
positive to the carbon or copper in the dark, 
it immediately becomes electro-negative to carbon 
or copper the moment it illuminated, — this 
being easily shown by the deflections of the 
galvanometer in contrary directions as the light 
is turned on and off.—Prof. S. P. Thompson: On the 
criterion of steel suitable for permanent magnets. 
Whatever the form to be given to a permanent 
magnet, the prime requisites as to the quality of the 
steel are (1) large remanent magnetism (I rem.) and a 

is 
high coercive (force Jf,). Since Hopkinson’s deter- 
minations of 1885 it has been supposed that for the 
purpose of making permanent magnets the best 
material would be that for which both of these quan- 
tities and, consequently, their numerical product, 
should be ‘as high as possible. Recently Mr. J. A. 
Mathews and, independently, Mr. J. R. Ashworth, 
have proposed to take the ratio I= em. or 
I+ Bom which only differs in scale as the criterion. 
To decide as to the suggestion to take the ratio 
instead of the product a table giving the values of 
ipl =I rem and Hi See, for a number of 
steels is given, and it is clearly shown that the use 
of the ratio as a criterion of magnetic usefulness leads 
to most absurd results. As an example, annealed 
manganese steel (almost non-magnetic) should, judg- 
ing from the ratio, be six times as good as Remy 
steel, whereas in reality, for equality of pull, a 
magnet of manganese steel would require to be 312 
times the weight of that made of Remy steel. The 
qualities requisite in an ideal steel for permanent 
magnets are indicated.—A. B. Wood and A. [. Steven : 
An investigation of the photographic effect of recoil 
atoms. The ionising, phosphorescent and_ photo- 
graphic effects of the a-particles from a radio-active 
substance entirely cease when the particle still retains 
about 4o per cent. of its kinetic energy. It appears 
possible, therefore, that the recoil atoms from a radio- 
active source should be able to affect a photographic 
plate, for though the range of a recoil atom is only 
about 1/sooth of that of the o-particle shot off from it, 
the ionising effect has been shown by Wertenstein and 
one of the authors to be ro times as powerful over 
the corresponding range as that of the o-particle. 
Attempts have, therefore, been made to demonstrate 
this action in the case of the recoil atom from 
polonium, this substance being chosen on account of 
the inactive nature of the recoiling atom. Two dis- 
tinct methods were employed: (1) The recoil atom 
was ‘‘absorbed’’; (2) the difference of deflection of 
the a-particle and the recoil atom in a strong magnetic 
field was utilised in order to attempt to separate their 
effects. ‘‘Schumann” plates were used as being most 
easily penetrable, but in all cases the results were 
negative or inconclusive. This is probably due to the 
fact that the recoil atoms are not able to penetrate 
sufficiently deeply into the sensitive layer to render the 
| grains developable. 

