Investment used in the casting practice in dentistry consists of a refractory, a binder and other chemicals. The refractory material is usually quartz or cristobalite. The binder material in the investment is some kind of calcium sulfate hemihydrate. Although varions types of physical test would be necessary to define a satisfactory investment, consistency of the slurry, which is directly related to the water-powder ratio used, is thought to be one of the most important properties that should be selected carefully. The proper water-powder ratio is generally determined by slump test. It is a simple practical test and it is not so closely related to fluidity of the investment slurry. The purpose of the present study is to find out a rheological parameter for fluidity of the imvestment slurry. First, the apparent vitcosity of investment has been measured by B-type viscometer, and then the reciprocal of the former (the apparent coefficient of fluidity) has been calculated. The coefficient has been used by the author as a parameter for fluidity. The present results show that the coefficient is a reasonable parameter for the investment slurry and that it is very useful for the clinical evaluation.

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The bone grafting for the repair of cleft lip, alveolar cleft and cleft palate is an important problem at the viewpoint not only esthetic effect for the lip and nostril area but functional relation of alveolar arch and palate. Since commencement of 1963, we have preformed the bone transplantation to fill or bridge the cleft space and prevent the collaps of the maxilla. At this report we referd to clinical obserbation and distant results for the 55 patientgroup (57 operation cases), they are treated in a year in 1963. In 20 of all 57 cases, autogenous local bone-chips were used as a graft. In 22 cases, heterogenous bone grafts (Kiel Bone) and in remained 15 cases, heterogenous bone grafts mixed with a small quantity of local bone-chips were used as a graft. The idea of utilizing the bone chips for implant material in various bone defects, created by surgical procedures in alveolar process and jaw bone, has been first suggested by M. Hirakawa, senior author of the present article. By the surgical closure of cleft deformities, especialy secondary repair, there are many amount of bone materials have been capable, which obtained from removal of overhanging bone of the maxilla and alveolus or correction of bone margins of the extraction wounds. We utilized these bone chips for a graft to fill the cleft space of maxilla, after prior antibiotics procedures. About principle technique to form the accept space for the graft, it is necessary an original idea and means, corresponding to each cleft types. We divided and discussed our opinions under five heads. As regard to the healing of operation wounds, we have satisfactory result, there are no tendency of remaining fistula or necrosis of transplnted bone in all 57 cases. At the clinical and X-ray observation on regeneration process of transplanted bone, we found fairly difference between the group of use of local bone-chip and the group of the heterogenous bones. In the cases where local bone chips were used, a remarkable new bone formation taking place around them was observed about 3 weeks after the operation, and a perfect restoration of the cleft space was observed by about 3 months after the operation. And yeareslater we observed functional reconstrucion of newly formed bone, corresponding to the mechanical reqiament on this site.

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Re-evaluating studies on the succinic dehydrogenase inhibition method, which was devised by Kondo et al. in 1964 were carried out. This is one of the screening tests of antitumor agents against the tumor tissue using triphenyl tetrazolium chloride. Sensitivity of four cancer tissues obtained from the oral cavity for the antitumor agents such as Nitromin, Mitomycin C, and Toyomycin was studied by this method. The results obtained suggest that the inhibition index measured by this method may be a clew for the choice of antitumor agent in oral cancer chemotherapy.

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During the dissection practice for students in 1964, the following three variations were encountered. 1) No.156 : age 50, male : The muscle, M. iliacus minor, is generally believed to originate from Spina iliaca anterior superior. The present case shows an interesting variation in that, the muscle originates with a tendon from Ligamentum iliolumbale at the middle part of the right Christa iliaca and by 8.8 cm median side of Spina iliaca anterior superior, fusing into M. iliopsoas. The length of themuscle was 8.2 cm, the width 1.5 cm and the thickness 0.2 cm. Presence of M. sternalis in the left side was also noticed in the corpse. 2) No.161 : age 48, female : The A. cystica branches usually from the Ramus dexter of A. hepatica propria, one of the branches of Truncus coeliacus, and runs into Vesica fellea. In this case, the artery arises as a branch of A. mesenterica superior and ascends to Vesica fellea without producing or receiving other branch on the way. This would be one of the rarest variations 3) No.164 : age 33, male : The A. renalis exhibts multiple variations either in terms of the numbers of branches in both halves of the body or in the location at which it branches off from the Aorta abdominalis. In the present corpse the kidney of the right side received two branches of renal artery with approximately the same diameter directly from the Aorta. But the upper one crosses behind V. cava inferior and the lower one in front of V. cava inferior and respectively reaches Hilus renalis.

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