Seven healthy guinea pigs about 450 grams each in weight were served as test animals. Tuberculin reaction was negative in every animal. About I/150mg. of tubercle bacilli of human type were laid into the dental pulps of mandibular incisal teeth of each animal. The animals were killed after the lapse of one hour, one, five, ten, twenty, fifty, seventy days. Toda-hara's, Fontes', Campbell's staining method and Haematoxilineosin method were adopted. Decalcifying agent was five percent formic acid solution. The results were as follows. Tuberculous lesions were found in alveolar bone and its bone-marrow, in submaxillary lymphatic gland, in lymphatic glands of cervical region, lymphatic glands of hilus hepatis, in spleen and lung. We could stain tubercle bacilli in dental pulps, in periodontal membranes and in other organs. We could not find, however, the characteristic tuberculous lesion in any dental pulp examined. We presume that tubercle bacilli may pass through dental pulp, and form the tuberculous lesions anywhere throughout the organism,

View full abstract

Penicillin resistant strains and penicillin susceptible strains of Staphylococus, isolated from the mouths of cheilosis individuls, were treated with sulfamerazine natrium and the following results were obtained. 1. Strains whieh are relatively ready to acquire the penicillin resistance and strains which are not so were isolated from the same lesion. 2. Penicillin resitant strains, when exposed in vitro to sulfamerazine natrium, have soon recovered the susceptibility to penicillin. 3. Experiments on mice have offered such results as to confirm the in vitro experiment that sulfamerazine played a part in promoting the resistant strains toward acquring susceptibility to penicillin.

View full abstract

The author exposed the sensory nerve from the femur of a grasshopper, cricket etc. and studied the action potential of the tarsus with tactile, thermal and contact chemical stimulation. Cathode ray oscillograph and elecromagnetc oscillograph were made use of. If one applys a light touch with a glass tube of 1mm diameter, there occurs a rapid change of potentials of about 200μv during the stimulation, and disappears with the cessation of the stimulation. The results by thermal stimulation can not be precisely ascertained. If a taste-sense stimulus be applied upon the tarsus, the potential changes is observed for each of 4 cardinal taste stimulations, the size being about 50μv. The frequency is very marked in the case of 4% NaCl, 3% acetic acid and 4% tartaric acid and not so much in the case of 3% sugar and 2% quinine. Applying taste stimuli to the tarsus elicited small action potentials in the sensory nerve which are easily distinguished from those elicited by touch. The peak heights of these small taste potentials are about 50μv, while those produced by touch amount to 200μv.

View full abstract

Hardness and elasticity of enamel and dentin of healthy permanet teeth from 6 to 7 by Mohs were measured by means of Dulometer, and the results were summarized as follows. Difference in hardness in diffent parts of a tooth was readily perceived. The difference seems to be based upon the degree of thickess of tooth's hard tissue. In dentin, local hardness difference was smaller than in enamel, and the difference became smaller toward the posterior teeth, which was inverse in enamel. Elasticity of dentin is also higher in posterior teeth than in anterior teeth, and the individual diviations are greater than those in enamel.

View full abstract

With an aim to know the possible environmental effects of hot spring region upon the developing stages of the young, 1914 grade school children and middle school boys in Beppu city were examined on physique, and 939 grade school children of Toyooka town having similar living conditions except lack of hot spring were laid as controls. It was concluded that the height, weight, chest girth and also Vervack-Wellisch index were excellent in the young of Beppu hot spring region than in those of Toyooka town. Hot spring seems good to the physique of the young.

View full abstract

The incidence rates of supernumeral teeth and crown anomalies among 11, 905 male and female population in Kyushu were studied, and the results were summarized as fllows. Supernumeral teeth occured at the rate of 0.79 percent in male, 0.44 percent in female, 0.61 percent in total. Geminated teeth appeared at the rate of 0.50 percent in male, 0.53 percent in female, 0.53 percent in total. Conical teeth appeared at the rate of 0.62 percent in male, 1.18 percent in female, 0.91 percent in total. Dwarf teeth occurd at the rate of 0.54 percent in male, 0.69 percent in female, 0.62 percent in total. Central tubercle of cusp (Yumikura) occured at the rate of 0.36 percent in male, 0.55 percent in female, 0.46 percent in total.

View full abstract

Ammoniacal silver nitrate solution, silver fluoride solution and Gottlieb's solution were applied on tooth surfaces to measure the caries inhibiting abilities. Three times during a year's course, each agent was applied on the right upper and lower first molars, and the first molars of left side were served as controls. D. M. F. tooth number was checked each time before the first application and four months after the last application. Caries inhibitions were observed in fourty two percent by silver impregnation method, in fourty one percent by silver fluoride method, while no inhibition was detected by Gottlieb method.

View full abstract

The ability of staphylococcus strains to coagulate blood plasms is influenced either by the amounts of bacterial cultures added, or by the types of blood plasms used. Based on these principles, we have conducted the numerous experiments which were to be outlined as follows. 1. The comparative tests were carried out on the plasms of rabbit, human, sheep, goat and guinea-pig. Human and rabbit plasms were more easily clotted by adding the cocci and proved more suitable for the test than those of the other animals. 2. Human and rabbit plasms were nearly equally susceptible to coagulation if prepared routinely by titrating a series of increasing dilution of plasms against a fixed volume of culture and better results were obtained by the use of broth culture rather than plate culture. 3. The optimal proportion could be obtained by mixing 5 times to 10 times dilution of human or rabbit citrated plasms in saline water and 1/8 to 1/32 mg. per c.c. dose of the bacteria of agar culture or 16 times to 64 times dilution of broth culture. 4. As to the relationship of the coagulase to the vilurence of the organisms, our experiments showed that coagulae-negative and haemolysenegative strains formed no toxins or were at least less toxic.

View full abstract