344. REPORT—1904. 
ferricyanide method and by the pump, i.e, by methods of a wholly 
different nature and on a different scale, the former method requiring 
lc.e. for each analysis, the latter 10c.c. 
In the case of the kidney we have obtained results of a similar 
character. The amount of oxygen taken in by the kidneys when they are 
not secreting, or scarcely secreting, is of the order of *5 c.c. per minute ; 
but in the injection of a saline diuretic, or urea, the oxygen taken in 
rapidly rises, and we have in one case got an exchange of 15 c.c. per 
minute. This is an isolated case, but an intake of the order of 5 c.c. 
per minute does not seem to be exceptional in cases of rapid diuresis. 
We performed several experiments to see whether the effests of a 
diuretic could be observed on the general respiration, and, on the whole, 
with negative results. The respiration becomes too much upset from other 
causes. These experiments gave us data for calculating what ratio the 
oxygen taken in by the kidneys, as previously determined, bore to the whole 
oxygen exchange of the dog. In the case of our last experiment a dog of 
the size we used would absorb about 60 e.c. of oxygen per minute. Its 
kidneys were using up 6 c.c. during diuresis—a tenth of the whole oxygen 
intake. 
We have not only noted the volume of the urine secreted, but also 
the ‘ work’ done, as indicated by the freezing-points of the urine and the 
serum. So far we have found that increase of oxygen and increase of 
work go hand in hand. 
Our experiments on the nitrogenous balance-sheets have not yet got 
past the stage of suiting the methods available to the purposes in hand.. 
Messrs. Laidlaw and Mottram have been working at the possibilities of 
Kjeldahl’s method and Gottlieb’s methods respectively. 
The oxidation taking place in any of the three glands named, the 
submaxillary, the pancreas, or the kidney, is many times greater than 
would be indicated by their mass. 
The Respiration of Plants.—Report of the Committee, consisting of 
Professor H. MarsHaLt Warp (Chairman), Mr. H. WaGrEr 
(Secretary), Mr. F. Darwin, and Professor J. B. FarMEr. 
THE money placed at the disposal of this Committee (15/7. in 1901 and 
12/7. in 1903) has been expended on apparatus for researches carried out 
by Dr. F. F. Blackman and Miss G. L. C. Matthaei. These researches 
deal quantitatively with the effect of temperature and light upon CO,- 
assimilation by green leaves. The relation between this process and 
temperature has been worked out in detail by Miss Matthaei, and the 
full account will be found in the ‘Philosophical Transactions’ of the 
Royal Society, Series B, vol. exevii. 1904, pp. 47-105. 
In this work attention was paid to several important points which 
had been neglected by previous workers. Of these, one is that all the 
leaves shall have been kept before the experiment under similar condi- 
tions of illumination and temperature ; and another, that the real internal 
temperature of the leaf under investigation shall be known. When work- 
ing with intense light, which necessarily heats up the leaf considerably, 
it was found practicable to arrive at the leaf-temperature thermo- 
electrically by inserting a fine thermo-junction into the substance of 
the leaf. 
