19-nortestosterone furylpropionate (Demelon), a newly synthetized anabolic steroid in Japan, showing an excellent anabolic effect on m. levator ani of the rat, was given by subcutaneous injection to 51 newborn babies weighing over 2501 g and to 26 immature babies, and the increase in body weight and the days required for the recovery of weight at birth were observed under consideration of the lactation and other factors.

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In the present report, phagocytosis-accelerating factor of saliva was investigated with special reference to the serum opsonin and the components of complement. Although the phagocytosis-accelerating activity of saliva appears always lower than that of the serum, it seems to take a part in non-specific resistance to infection of invasive microorganisms in the oral cavity, and may be called saliva opsonin. Even if saliva opsonin is not always identical with serum opsonin because of its lack of C3' or/ and C4', it may consist of a part of serum globulin, or C1' and a minute amount of serum albumin or C2' which enforces the activity of the former. On the other hand, in cases of dental caries, opsonic activity is remarkably decreased in spontaneously secreted saliva, although sucked saliva from the opening of salivary glands retains intact opsonic activity; and the decrease of opsonic activity in carious cases is examined from the distribution of lactobacilli, the supposedly causative agent of the dental caries.

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Cast restoration s are some times reheated in investment for soldering or repairing. In this study, distortion of castings made of gold alloys of types B and C and a dental copper alloy due to reheating in investment was investigated by reading the degrees of their cervical misfit on the original dies before and after reheating. The effect of reheating without investing was also compared as control. Findings were as follows: 1. Reheating could distort the castings remarkably in investment but little without investment. 2. Slender U-form castings distorted more than heavier M-O-D castings did. 3. Distortion was greater in a quartz investment than in a cristobalite investment. 4. The reheating· temperature to produce clinically significant distortion was higher than 600℃ for the copper alloy and higher than 800℃ for the gold alloys. Dental castings are sometimes reheated in investment. For instance, a defect in a cast restoration may be repaired by adding another cast or solder with reheating the casting. If the units for a bridge or splint are connected by soldering, they are also reheated in investment. The change in relative position of those units during soldering has so far been discussed as the main cause distorting a bridge or splint1-5). The distortion of the units themselves due to reheating in investment must also be considered. Such a distortion was investigated in this study, varying form of casting, types of investment and alloy, and heating temperature.

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The present study was carried out to investigate on the time of each phase in cell cycle of the tooth germ cells (internal enamel epithelial cell and pre odontoblast) and the effects of X-irradiation on the cell cycle by means of autoradiographic method with tritiated thymidine. Upper incisors of rats (Wistar strain) were used as materials. Generation times were estimated to be 27.3 hours in internal enamel epithelial cells and 25.3 hours in pre-odontoblasts, respectively. Both labeling index and photographic grains per cell on autoradiograms were markedly decreased in internal enamel epithelial cells and also in pre-odontoblasts as early as one half an hour after 1,200 R of single X-irradiation.

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