666 TRANSACTIONS OF SECTION M. 
Further discussion :— 
Prof. W. A. Ossorne: Investigation of skin temperatures has a quite 
different significance when the shade temperature of the air is equal to the 
normal temperature of the animal. In this case, even in the driest-skinned 
animals the skin temperature is generally below that of the air. When the 
shade temperature of the air is higher than that of the animal the skin tempera- 
ture may be higher than that of the internal organs. 
Thickness and texture of coat and thickness of skin are factors of some 
importance. 
Prof. B. Moore: In the photosynthetic processes by which aldehyde is first 
formed the association of colloidal iron salts with the colourless organic portion 
of the chloroplast plays a distinct part. The metabolic conversions occurring in 
plants and animals from one type of carbohydrate to another are not difficult to 
account for by simple enzyme action because the energy charges are so slight, 
but the synthesis in the metabolic processes of protein and fat from carbo- 
hydrates requires a linkage and co-ordination of an endothermic with an 
exothermic reaction, such as has never been observed with a simple enzyme. For 
such synthesis an adsorption of enzymes into the cell protoplasm is required so 
as to furnish a colloidal regulating mechanism able to alter its activities from 
one time to another, and to build up or break down according to the demands 
of metabolism. 
In certain invertebrates and fishes there is an excessively low rate of 
metabolism, and a relatively enormous portion of food energy is thrown into the 
metabolism of the sex organs in such animals, as compared with the somatic 
metabolism. 
Mr. G. P. Darnetz-Smitu: The first visible product of assimilation in 
plants is starch, and the absence of visible starch in a plant does not show 
that it is incapable of forming it, but that its metabolic processes and its rate 
of translocation are so rapid that there is no need for starch to be deposited. 
For starch is to be regarded, not as a first product of assimilation, but as a 
substance that is thrown down temporarily by rapidly assimilating plants until 
such time as the plant is able to deal with its translocation. Brown and Morris 
regarded cane sugar as the first product of assimilation, but a critical examina- 
tion of their experimental results fails to carry conviction. 
As regards enzyme action confusion is introduced by comparing it with, for 
example, the rate of hydrolysis produced by acid. It has to be remembered 
that an enzyme is a colloid, and that the action of a colloid is determined by its 
previous history. Unless the previous history of a colloid is known, its 
action cannot be predicted; hence a portion of any particular colloid under 
particular conditions will act in a different manner from another portion of the 
same colloid (but with a different previous history) under the same particular 
conditions. 
Mr. D. McAtpine: The question whether chlorophyll has any action in the 
green plant in the absence of sunlight is uncertain. Its photosynthetic activity 
is probably slight, yet it is found where sunlight could not possibly penetrate, 
as, for example, in the so-called fruit of the yew, the seeds of the lemon, and in 
the conducting parenchyma throughout the tissue of the apple. 
(ui.) The Distribution of Nitrogen in the Seeds of Acacia Pyenantha. 
By Dr. J. M. Perris and Dr. H. G. Cuapman. 
The seeds of a pycnantha which have been dried in the air contain 4'5 per 
cent. of nitrogen. If the testa be removed the seed contains 5:5 per cent. of 
nitrogen. The nitrogen is present partly as protein and partly as various organic 
compounds. 
The nitrogen present as protein forms 55 per cent. of the total nitrogen. The 
protein soluble in water contains 26 per cent. of the total nitrogen; that soluble 
in 10 per cent. NaCl 13 per cent. of the total nitrogen, and the remainder 
could not be extracted. Protein soluble in alcohol is absent. Protein coagu- 
lable by heat contains 10 per cent. of the total nitrogen. 
The nitrogen present after precipitation with 80 per cent. alcohol amounts to 
45 per cent. of the total nitrogen. 
