LONDON. Royal Society, May 18.—Sir Charles Sherrington, president, in the chair.—T. B. Wood and J. W. Capstick: The progress of metabolism after food in swine. Using a calorimeter recording electrically the main loss of heat, the resting metabolism of a hog has been recorded at intervals after feeding, varying from a few hours to six days. The excess of the resting metabolism above the basal, at any moment, is independent of temperature, weight, and age of animal. This excess falls off according, to the equation logy + Ai = C, y being the excess, t time since meal, and A and C constants. This equation is identical with Guldberg and Waage's Law of Mass Action, that the rate of decomposition of a substance at any time depends on amount remaining undecomposed. Analysis shows that the excess depends on the pressure in the body of substances resulting from digestion and affecting the rate of metabolism, which are themselves metabolised according to the mass-action law.—J. A. Gardner and F. W. Fox: The origin and destiny of cholesterol in the animal organism. Pt. XIII.—On the autolysis of liver and spleen. The autolysis of pulped spleen and liver, during periods varying from one day to a month, shows that the cholesterol content remains' constant, within the limit of experimental error, and the addition of pure cholalic acid has no effect. Autolytic experiments afford no evidence that these organs are concerned with the synthesis or destruction of cholesterol in the organism.—C. G. Lamb: The geometry of insect pairing. Cases of asymmetrical hypopygium found in certain dipterous families, and in other insects would necessarily result if the usual vertical position of pairing was adopted subsequent to a primitive linear position.—G. E. Briggs: Experimental researches on vegetable assimilation and respiration. Pt. XV.—The development of photo-synthetic activity during germination of different types of seeds. The seedling leaves of Helianthus showed practically full activity immediately after germination, both when light and when temperature were limiting. Other plants showed practically none. In the type showing the lag between germination and development of photosynthetic activity, the seedling possesses a specialised photosynthetic organ separate from the storage organ, while in the other type the same organ serves the dual purpose. Pt. XVI.—The characteristics of subnormal photosynthetic activity resulting from deficiency of nutrient salts. Phaseolus vulgaris was grown in a complete culture solution, and in culture solutions devoid of potassium, magnesium, iron, and phosphorus, respectively. The assimilation of leaves from the plants was measured by determining their output of oxygen. Two types of determinations were made: in one the intensity of illumination was so small that light was limiting; in the other, the intensity was increased until assimilation was limited by temperature. Plants grown in normal solution showed greater photosynthetic activity, and in the others the depression was the same when light was limiting as when temperature was limiting. Probably the factor inside the plant involved is the amount of “re-active chloroplast surface.” Therefore activity should be'sub-normal when carbon dioxide is limiting, a condition for which some evidence exists.