Nerve distribution in the salivary glands of adult rats and possible relation between the patterns of distribution in successive stages of the growing glands were investigated histologically. For the initial phase of study, three major glands from adult albino rats, and for the second, the parotid gland specimens successively taken from infant animals directly after birth, were respectively used. The results were summarized as follows. Nerve Distribution in Adult Salivary Glands : 1. Submandibular and sublingual glands in the albino rats were enclosed in the same integument and had a hilus in common. There were in the connective tissus of the hilus numerous nerve cells forming ganglia of varying sizes. In the parotid gland, however, similar nerve cells were found neither in the hilus region nor in the glandular body. 2. The majority of nerve fibers entering in the salivary glands assume the appearance of socalled terminalreticulum which is known as normal terminal form of the vegetative nervous system, and in this form were they distributed in the terminal acini, over the entire duct systems and the wall of blood vessels nourishing the glandular body. since anastomosis was observed to occur everywhere between each terminalreticulum, it was thought improbable that it exerted some sort of autonomous nervous regulation on its limited region. In fact, all these terminalreticulums formed together an integrated system of network. Microscopic differentiation of the reticulums as to whether they were of sympathetic or parasympathetic origin could not be determined. 3. Coming out of these terminalreticulums, there were seen fibers of more finer structure distributed in the terminal acini, granular ducts and striated ducts, entering as far as into individual acinus, between individual cells of the acinus and into the duct cells and their periphery. The ways in which these fibers were distributed in those parts of the organ could be by appearance divided into two types. In the one type the fibers were seen as a single strand thickly stained with silver, and in another they run in varicose fibrils forming broom or network structure. The former type was mainly seen in the striated ducts and granular ducts, the latter type mainly in the terminal acini. 4. As the ways in which nerves distributed themselves differed with each individual parts of the organ, so the amounts of nerve supply also differed from one locus to another of the same organ and from one gland to another. In the parotid and sublingual glands, the most abundant nerve supply was seen in the terminal acini, followed by the striated and intercalated ducts in this order, and it was poorest in the glandular duct where hardly any sign of nerve supply was observed. In the submandibular gland, however, extremely abundant supply of nerve fibers was found in the granular ducts having the anatomical feature characteristic of this gland. The nerve supply for the remaining parts of the gland followed the patterns similar to that described for parotid and sublingual glands. Amounts of nerve supply were not homogeneous even within each section of the same organ through every glands. 5. In the hilus part there were observed a few instances of a simple, sharply tapered free endings usually encountered in the terminal form of sensory nerve and another terminal form resembling the glomerate ending, through every glands examined. Relation between Growth of Parotid Gland and Its Nerve Supply : In the parotid glands of the post-natal animals, there was seen a multitude of clusters of immature cells, dispersed in the loose fabric of connective fibers. At this earliest stage, around the clusters of immature cells which still lacked basilar membrane, the nerves distributed themselves in the form of the terminalreticulum consisting of extremely fine fibrils. These terminal apparatus were also seen distributed in the connective tissue binding the

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Dental caries incidence and age effect were studied on individual permanent teeth in terms of DMFT found in a total of 16572 male and female pupils of public schools ranged in age from 6 to 14 years. The results are summarized as follows. 1. Comparison of DMFT and the rate of DMFT found in three residential groups of subjects, suburban, urban and isolated islet, revealed that both values were highest in the urban, followed by the suburban groups and lowest in the isolated islet group. Possible reasons for the difference may be searched mainly in the diet habits, especially difference in the kinds of foods usually taken, in the cooking procedures and relative amounts of sweets consumed. 2. There was not found any noticeable difference between three subject groups with regard to the caries incidence relative to age stage with 28 permanent teeth examined. The rate of DMFT for every teeth was highest in the urban group, foollowed by the suburban, and lowest in the isolated islet group. 3. Comparison of the age-linked caries incidence for every tooth between male and female, showed that the rate was higher in the female than in the male. However, the sequence in vhich every tooth on each jaw suffer decay with advancing age was found identical. The molars and premolars showed higher incidence in the lower than in the upper jaw, while the anterior teeth showed reverse trend. The firet molar showed decay at the rate of more than 13% a early as 6 years of age, which approached to 50% by the age of 14. Emphasis should be given to the need of dental care for the infants from the time directly after eruption of the permanent teeth. The first and second premolars in both jaws were likewise extremely susceptible to the post-eruptive decay, but the progress of the decay with age was not rapid. Early dental care is also indicated on these teeth. The most marked increase of decay with advancing age was observed in the seeond molars. These teeth should be under surveilance throughout the time to come against the decay.

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A physical examination was undertaken on a total of 2140 male and female pupils of primary and middle schools in Miyakonojyo city, Miyazaki Prefecture, as of the year 1950. For the physical examination, body height, body weight and chest girth were measured, and for study of the physical strength, 50 meter running, standing broad jump and soft ball pitching were imposed on the subjects and the results were recorded. The data obtained were analyzed by comparison between both sexes groups and between the state-wide average values for the year 1960 and the results were summarized as follows. 1. The physique as well as the physical strength in the present group were both lowest at the age stage of six, but gradually being improved with advancing age. The male exceeded the female in every respects. 2. Comparison between the present data and the state-wide averages revealed the following. 1) The values for the chest girth in the present subjects excelled slightly the statewide average, while those for the body height and weight were inferior the state-wide averages. 2) The present group excelled in 50 meter running, but fell behind in standing broad jump and soft ball pitching. 3. Except for the chest girth and running attainment, the present group seems to fall behind the state-wide average in both physique and physical strength.

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Morphology of the premolar crowns was studied on the plaster models of upper and lower jaws taken from 683 Japanese residents of both sexes in Kyushu district. The results were summarized as follows. 1. In the values of measurement for width and breadth of the crowns, those for the male were greater than those for the female, and as to individual teeth, those for the first premolar were greater than those for the second in the upper jaw, while in the lower jaw the relation between the two was reversed. 2. Measurement of the width and breadth indices of the crowns showed that the crowns of premolar teeth had in general greater bucco-lingual, and smaller mesio-distal diameters. However, comparison of both jaws in this respect revealed that the crowns of the premolars in upper jaw had more flattened mesio-distal diameter than those in lower jaw. 3. With respect to the number of cusps in the lower premolars, it was found that bicuspid occupied more than 90% of the first premolars and in contrast tricuspid occupied more than 50% of the second premolars, clearly indicating decreasing trend of bicuspid in the second premolars. 4. The shapes in which the occlusal grooves occur in the premolars of both jaws were classified into 5 types, A, B, C, D, E, according to the degree of degeneration observed. Following the classification, the type A represented the standard form of the occlusal groove in human premolars and the remaing types represented in the order successively degenerated forms, with the type E coming as most degenerated form. Analysis of frequency distribution of these types in every teeth of jaws disclosed that in the upper first premolar Type A predominated, followed by Type B, and the remaining forms rarely occurred. In the upper second premolars, Type C was predominant, followed by Type B, and Type A was the rarest. With premolars of lower jaw, Type E occupied the majority of the first premolars with small occurrence of Type C, and the remaining types were hardly observed. In the second premolars Type C was predominantly seen, followed by Type B and Type A in the order. 5. Occurrence of the marginal tubercle in the premolars of upper jaw was observed in the majority of the first premolars, but only in as few as 22% of the second premolars. 6. The position of the lingual cusp was measured as to whether it was located more distally or mesially against the bucco-lingual median line of the crown or it was on this line. The results showed that the majority of the teeth in both jaws was located mesially. However. the teeth having the cusps centered or located mesially occurred more frequently in lower jaw than in upper jaw. 7. Development of the disto-lingual cusps in the lower premolars was weaker in the first and considerably greater in the second. 8. Development of the crossing ridge was observed in the majority of the first premolars, but hardly observed in the second premolars in lowere jaw. 9. Caninisation of the lower first premolars was observed in approximately 50%. It has been a generally accepted concept that human teeth were undergoing degenerative process from backward teeth. This concept would lead to the assumption that the second of the premolars show more advanced stage of degeneration than the first. The results of the present study, especially, in the reduction in the number of occlusal cusps, the changing types of the occlusal groove, the frequency distribution of the marginal tubercle in the upper premolars, the caninisation in the lower premolars and the relative magnitude of individual teeth, furnished, on the whole, apparently conflicting evidences between the teeth of both jaws, and these evidences showed more advanced degeneration in the second premolars than in the first premolars with upper jaw, and not with lower jaw, where conversely the first premolars apparently suffered more advanced degeneration.

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Lingual papillae were histologically studied on a male Ammotragus lervia aged 4 and a male sheep aged 12. The results were summarized as follows. 1) In both animals Papillae vallatae were located on the dorsal surface of the posterior part of the tongue. They counted in the Ammotragus lervia 12 to 15 arranged in a row and in the sheep 20 to 25 arranged in two to four rows along each side of the tongue. The taste buds counted approximately 5 to 10 in the Ammotragus lervia and 4 to 5 in the sheep along each side of the tongue localized on the epithelium facing the circumscribing groove of the papillae. 2) Papillae fungiformes were distributed over the entire dorsal surface of the tongue, and especially densely on the dorsal surface and the lateral margin of the anterior part of the tongue. In both animals they counted approximately 200, and lacked the taste buds. 3) Papillae filiformes occurred as needles covering the entire dorsal surface and the lateral margin of the anterior part of the tongue.

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