Societies and Academies

Abstract

EDINBURGH. Royal Society, June 3. - W. C. M'Intosh: On abnormal teeth in some mammals, especially in the rabbit. In the Primates the chief irregularities are the development of extra molars, the narrowing of the tip of the lower jaw so that the incisors and canines are crushed from their normal positions, asymmetry of the muzzle, gaps between the teeth, and bulging of the rows of grinders internally or externally. In the Carnivora, gaps between the incisors in the maxilla and mandible, displacement and duplication of canines and duplication of incisors are found. In forms suffering from peridentitis salivary calculi occasionally occur. Displacement of a canine may be accompanied by an aperture in the hard palate into which the tooth fits. About twenty Rodents other than rabbits have been found with abnormal teeth, amongst which striking cases exist in the beaver, hare, and the brown rat, the right man-dibular incisor in the former making more than a circle and penetrating the soft parts. In the teeth of the sperm whale the dentine and cement may be diseased and abraded. The folding of the root of the small tusk of the female dugong is noteworthy. In the Ungulates and marsupials numerous abnormalities present themselves. Special attention was devoted to the rabbit, abnormal teeth in which were described in about 100 cases and grouped temporarily into (1) those with the upper incisors more or less symmetrically curved outward; (2) upper incisors deflected to one side; (3) upper incisors curved into the mouth. The old view of such dental abnormalities being due to external injury must be abandoned, since in every group congenital causes or diseases were usually at the root of the abnormalities. -Ian Sandeman: Bands in hydrogen related to the Fulcher system. The 33S ->o 23S system of Richardson and Das is extended, the band previously given as the null band (0, 0) now being taken as (2, 0), while two additional vibrational levels are added on the infra-red side.-J. A. V. Butler and W. O. Kermack: The action of salts of polynuclear bases on colloidal suspensions and on the electro-capillary curve. In small concentrations, salts of 5: 6-benz-4-carboline and its derivatives effect precipitation of colloidal gum benzoin and other negatively charged lyophobic colloids, but when higher concentrations are used no precipitation occurs and the colloidal particles acquire a positive charge. Experiments on the precipitation of colloidal gum benzoin by mixtures of benz-carboline and gelatin indicate that the presence of the gelatin tends to decrease the adsorption of the benz-carboline. Benz-carboline sols, present in low concentration (M/20,000), exercise a marked effect on the electro-capillary curve of mercury, the depression being maximum on the positive side of the maximum of the primary, that is when the mercury is positively charged relative to the solution. The results indicate that benz-carboline ions undergo marked adsorption even on a positively charged surface.-Sir Thomas Muir: The theory of skew determinants and pfaffians from 1891 to 1919.