The effect of transplacental administration of ethylurethan on the mitotic activity in the hand plates of mouse embryos was investigated. On the 12th day of gestation, 10% ethylurethan was injected intraperitoneally to pregnant mice, and on various hours up to 7 hours after injection, a number of precartilage cells in each stage of mitoses was counted. In 7 hours after administration, a conspicuous decrease of mitoses was recognized in all the stages. Namely, ethylurethan may have shown the effect of the trypaflavin type toxins.
It may be considered that digital malformations of embryos induced by injection of ethylurethan was caused by the inhibition of mitotic activity in the cells of the bone primordia of digits.

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The adrenal cortices of male mice of D. D. strain respectively castrated at the 10th and 40th postnatal day were histologically observed with a particular remark to the fate of X-zone and the results were as follows:
Both organ and body weight tended to increase more exceedingly than those of non castrated control in the corresponding postnatal days, and in early castration group (10 day) they showed a more marked increase than in late castration group (40th day). In male mice early catrated, X-zone which is naturally destined to be shrunk on the normal course of postnatal development was succeeded conversely by the gradual proliferation inherent in the level of non-castrated female mice. The cell population of X-zone began to grow profoundly from the 15th day following the castration, and its consistuent cells became to be activated in their shape and internal structure. On the contrary a sign of degeneration in X-zone was concurrently brought with the augmentation in size and in 40 to 60 days the thorough involution appeared, resulting in atrophic pattern of X-zone. However this zone was inclined to increase in size again after the 90th day in equilibrium with the degree of degeneration. In lately castrated mice, X-zone which was to be naturally involuted on way of normal postnatal development grew in size and proliferated by the castration, but, being compared with the progressive change in early castration group, the morphological response in late castration was less serious and dilatory, presenting no formation of indepelndent cell layer with the precise border, but only simple cell groups scattered at the periphery of the medulla resembling the character of X-zone. The islet-like groups whichy consist of X-zone cells did not provide the active internal structure, and they were before long dispersed in the lapse of time. In a word the acting power to hypertrophy the X-zone by the castration was stronger in case of using the immature animals as the materials than in the event of using adult animals.
As to the definition of X-zone, we prefer to formulate it as the independent cell layer providing the active cellular pattern in response to the internal environment of living body, rather than mere atrophic remainder of the fetal cortex. And despite any conclusion was not drawn from present investigation concerning what kind of hormones are secreted out of the X-zone and their hormonal regulation mechanism, we discussed these problems from the present issues.

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The sensory nerve supply of the urethra of goat is naturally poorer than in the higher mammals, including man, dog and cat, especially so in the pars cavernosa urethrae. In this part, the number of sensory fibres is very small and their terminal mode could not be elucidated as distinctly as desired, the excellent impregnation method I used notwithstanding. It was found, however, that some small-sized genital nerve bodies Type I and Type II were present in many places in the tunica albuginea of the corpora cavernosa, besides some simple branched terminations.
The pars praeprostatica urethrae is better supplied with sensory nerves than the pars cavernosa above. The sensory terminations are, however, only very simple ones formed subepithelially or more rarely intraepithelially, comprising unbranched and simple branched terminations originating in medium-sized fibres.
The pars muscularis urethrae is the best provided with sensory fibres and their terminations of all the parts of the goat's urethra. The terminations found here comprise a number of complex-typed ones, such as complex branched terminations and corpuscular terminations. It was of deep interest that capsulated genital nerve bodies Type I and Type II, never to be found in the urethra of dog or cat, could be observed in the m. urethralis of striated nature of goat, and that in large size and complex form. Often the Type II bodies were found to contain branched inner bulb with a terminal fibre per branch, in a common connective tissue capsule.
The submucosa and the propria of the pars muscularis urethrae, corresponding the pars prostatica of the human urethra, contain nerve plexus containing thick sensory fibres, which mostly end in branched terminations, but besides glomerular terminations of non-capsulated type composed of terminal fibres showing frequent change in size and containing numerous cell nuclei are not rare either.
Branched terminations are found in a considerable number beneath or within the epithelium of this part. The subepithelial terminations comprise unbranched, simple branched and complex branched ones, very often spreading over a large terminal area and having terminal fibres showing more or less marked or sometimes no change in size. The intraepithelial branched terminations are also formed in a rather complex manner. Their terminal fibres usually show little change in size and only very rarely reach the superficial layer of the epithelium.

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No EIMER's organs (BOTEZAT, BOEKE) containing the so-called tactile cells could be found in the epithelial cristae in the snout of mole. These cristae are somewhat lower than those in cat and have often slightly concave basal surface. They are similar to those of cat in structure and are made of epithelial cells of uniform nature in all parts.
The connective tissue between the cartilage of the vestibulum nasi and the snout is invaded by a very large number of nerve bundles, which branch out into small bundles as they run toward the epithelial cristae. The sheaves of several sensory fibres each reaching beneath the cristae mostly end in unbranched and simple branched terminations composed of short thick terminal fibres showing conspicuous change in size formed subcristally (intracristally in cat), but sometimes in small-sized corpuscular terminations. The terminal fibres of the branched terminations sometimes run further into the epithelium to form intraepithelial fibres and not rarely right through the cristae up as far as into the superficial layer of the epithelium, before ending sharply or bluntly.
The corpuscular terminations never form PACINIan bodies (BOEKE and BOTEZAT) but always appear in the form of elongated club-form end bulbs encased in thin connective tissue capsule. Their inner bulb consists of an outer bright zone containing a few ovoid nuclei and a dark-staining inner axial zone, into which runs a thick sensory fibre that ends near the distal pole of the inner zone in blunt point without branching out. These end bulbs, somewhat different from the PACINIan bodies as allegedly found by BOEKE, are sometimes found in groups of 2 or 3 beneath one crista and often in the connective tissue of deeper layer.
The existence of such terminations of two types beneath the epithlial cristae morphologically suggest that they respond to external pressure exerted on the cristae as if a taut spring is released.
A narrow hairless skin part surrounds the snout. A considerable number of sensory fibres are found running into this part, forming unbranched and simple branched terminations and end-bulbs as in the snout above, here mostly in the short papillae. The end bulbs are found not only subepidermally but also in the deeper layer of the propria and are sometimes more complex in form than those in the snout, containing 2 or 3 branch fibres in their inner bulb.
Besides the common hair follicles, a considerable number of sinus-hair follicles are found in the haired skin around the snout. The former comprise very small-sized and large-sized follicles. The latter in mole are far smaller in size than in some higher mammals (monkeys and dog) and have very ill-developed sebaceous glands, but the connective-tissue terminal areas of sensory fibres specific to hair follicles are in marked formation around the outer epithelial follicle layer in the upper part of these sinus-hair follicles, as well as in the common hair follicles.
A rather large number of sensory nerve fibres run into this haired skin too. Most of them proceed toward the hair follicles, more frequently to the sinus-hair follicles, only very few of them running subepidermally.
The nerve supply to the small-sized common hair follicles is very poor, many of them being utterly unprovided with sensory fibres. In the large-sized ones, however, sensory fibres are found coming into the terminal area in the follicle neck to end in simple branched, and more frequently, fence-like and plexus-like terminations therein.
Into the sinus-hair follicles, a much larger number of sensory fibres are found coming in, not only from the basal or lateral sides of the follicles as usual, but also from the top side, as never observed in any other mammal hitherto. Thus, the stem fibres forming terminations inside the terminal area of the sinushair follicles in mole may be divided into ascending and descending fibres. The terminations they form

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The human sebaceous glands were observed with the electron microscope. The youngest cell contains a few mitochondria, smooth surfaced vesicles and tonofilaments. As the cell grows, small dense granules appear abundantly, but tonofilaments diminish. Smooth surfaced vesicles are multiplied and lipid droplets are produced and enlarged.
Mature cells are filled with extremely large lipid droplets and abundant vesicles which make appearance of the cell like a sponge. Small dense granules markedly decrease in number. The nucleus becomes to be irregularly shaped with an extremely dense karyoplasm, which is ready to the death of the cell converting into the sebum.
It is tentatively assumed that the lipid droplets may be transformed from mitochondria, and that the origin of smooth surfaced vesicles may be ascribed to the small dense cytoplasmic granules.

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Es glückte die Mitochondrien in den Fasern des Ischiadicusnerven und in den Dendriten der PURKINJEschen Zellen der Kleinhirnrinde des Kaninchens durch die Versilberung nach FUJII schwarz im violetten Ton darzustellen. Die Nervenfasern wurden in dem Elektronenmikroskop untersucht. Dabei wurde beobachtet, daß zahlreiche Silberteilchen von etwa 30mμ sich besonders reichlich in den Mitochondrien ablagern. In den an Dehydrogenasen reichen Mitochondrien scheinen sich frühzeitig kleinste metallische Keime für die nachträgliche Silberablagerung zu bilden und zu entwickeln.

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Human axillary eccrine sweat glands obtained from an aged healthy male individual were examined with the electron microscope.
The cytoplasm of both superficial and basal cells of secretory epithelium contains many bundles of tonofilaments. The basal cell is usually seen darker than the superficial, due in part to the presence of abundant small granules of medium density, which are considered to be particulate glycogen.
Electron microscopic findings to be regarded as senile phenomena are generally identical to those found by IWASHIGE (1952) with the light microscope. They are: 1. atrophy of the gland cells and dilatation of intercellular canaliculi caused therefrom, 2. disappearance of secretory granules, 3. multiplication of fat droplets both of solid and polyvesicular type, and 4. swelling and fat deposition of the myoepithelial cells. Some degenerated gland cells are found and may be added to the characteristics of the senile sweat glands.

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The mucous membrane of the tongue of flyig-squirrel may be called rather rich in sensory nerve supply, but far lese rich than the same of man and other higher mammals studied hitherto. The foremost part of the dorsum linguae and the entire facies inferior linguae with poorly developed propria contain only very poor proprial plexus and consequently the number of sensory fibres cming from this plexus is very few. Only the fungiform papillae found sporadically in the foremost part of the dorsum linguae have often well-developed proprial plexus under them. The propria is well developed in the middle and the psoterior parts of the dorsum linguae and the radix linguae, permitting good development of the proprial plexus.
The sensory supply to the filiform papillae is very poor in the foremost part but grows better in the parts more to the rear of the dorsum linguae and falls off a little again in the radix linguae. So, the sensory innervation of the papillae in these parts runs parallel with the size of the papillary stocks. Namely, the very ill-developed filiform papillae found in the foremost part are devoid of sensory fibres, except the few somewhat stouter papillae found in this part into which 1 or 2 sensory fibres run and end in unbranched terminal fibres therein. The considerably well-developed filiform papillae in the middle part of the dorsum linguae are always supplied with sensory fibres which end in simple and complex branched terminations; the terminal fibres of these often show very perceptible change in size and sometimes end after penetrating the epithelium very slightly. The filiform papillae with the largest stocks found in the hinder part of the dorsum linguae are the best provided with sensory fibres and their terminations among all the filiform papillae. These terminations include not a few uncapsulated simple glomerular terminations. The filiform papillae in the radix linguae are somewhat worse developed than those in the preceding part.
Into a fungiform papilla, a rather thick nerve bundle composed of a few medium-sized sensory fibres and many fine vegetative fibres comes in and spreads out in the top part of the stock. The sensory fibres end in unbranched and simple branched terminations beneath the taste-budded epithelium, and only a very few of the terminal fibres in intra- or extra-gemmal fibres. The vegetative fibres end in terminal reticula as always.
In the lateral margins of the rear part of the dorsum linguae of flying-squirrel are found formations taking place of the foliate papillae in the upper and lower walls of the longitudinal deep furrow located there. The propria of both the walls contains complex ground plexus sometimes containing a number of REMAK's hemiganglion cells. This plexus consists of numerous fine vegetative fibres and a fewer thick sensory fibres, of which the former end in well-developed terminal reticula beneath the taste-budded epithelium, while the latter form simple and complex subepithelial branched terminations with terminal fibres often enough of thick size and not rarely ending intra- or extra-gemmally.
The vallate papillae on the tongue of this animal are very few but well developed and have very well-devloped ground plexus containing some REMAK's hemiganglion cells in their basis; these plexus containing numerous fine vegetive fibres and fewer sensory fibres run into the papillary stocks and spread out the nerve fibres toward the taste-budded epithelium, beneath which the terminations are formed, just in the manner as in the taste-budded furrows. The sensory terminal fibres here too often form intra- and extragemmal fibres. Well-formed branched sensory terminations composed of thick terminal fibres are found in a rather large number in the taste-budless epithelium in the basis and the encircling wall of the vallate papillae and the terminal fibres from these terminations frequently end inside the epithelium.

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The effects of X-ray radiation with a dose of 500r on the secretory activity of the gastric chief cells of rats were studied. The results are summarized as follows.
1. The effects of X-ray radiation on the secretory activity of the gastric chief cells have no connection with areas exposed.
2. The secretory activity of the chief cells, viz. production and discharge of secretory granules decreases positively after the irradiation.
3. The discharge of the histamine-like gastric hormone productin (FUJIE) from the gastric surface cells is slightly less after the X-ray.
4. These changes are a little more mild in the animals receiving daily 100r for 5 days than in the animals receiving a single dose of 500r.
5. The effect of histamine on the secretory activity of the chief cells decreases and the effect of the decomposed product of histamine increases, if injected subcutaneously prior to the X-ray irradiation.
These findings suggest that the hypofunction of the gastric chief cells induced by X-ray radiation is attributable to the fact that the action of the discharged gastric hormone productin is inhibited by a certain substance which might have been produced in the tissue irradiated.
6. The protective effects of polyvinylpyrrolidon, thioctic acid and 5-oxy-anthranilic acid on the X-ray injury in the gastric chief cells are found to be not so remarkable. Only some of the functional derangements in the chief cells are slowed up by the use of these agents.

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Bei den ein ganzes Jahr hindurch monatlich angesammelten 62 ausgewachsenen Schlangen (Elaphe quadrivirgata) wurden LANGERHANSschen Inseln des Pankreas histologisch und cytologisch beobachtet. Für die Fixierung wurde vorwiegend ZENKER-Formol und für die Färbung der Paraffinschnitte hauptsächlich Azan angewandt.
1. Bei der Elaphe quadrivirgata kommen LANGERHANSsche Inseln in der Regel entlang den verästelten Schaltstücken des Ausführungsgangs vom exokrinen Pankreas vor und weisen darauf hin, daß sie sich von den Schaltstücksepithelien entwickelt haben. Innerhalb des Inselgewebes werden nicht selten die wahrscheinlich der Schaltstückslichtung entsprechenden, spaltenartige Kanäle wahrgenommen, welche entweder von eigentlichen Schaltstückepithelien oder Inselzellen selbst umgegeben sind. Auf Grund dieser Befunde läßt sich der Schluß ziehen, daß bei der Schlange den Inseln außer der inkretorischen Tätigkeit noch die Ableitungsfunktion des Sekretes der exokrinen Acini zukommt.
Auf der Oberfläche der Insel ligen oftmals die mehr oder weniger abgeflachten exokrinen Acini gleichartig wie Halbmonde der gemischten Speicheldrüsen der Säuger an, diese sind nichts auders als die den Zweigen eines Schaltstückes angehörige Acinusgruppe. Zwischen den Acini und der Insel findet sich keine bindegewebige Scheidewand, so stehen sie in einem direkten Zusammenhang; dort kommen nicht selten zerstreut Schaltstückepithelien oder centroazinäre Zellen und die oben erwähnten spaltenartige Kanäle vor.
Bei der Schlange verteilen sich viele verhältnismäßig kleine Inseln im ganzen Bezirk des Pankreas, ihre Verteilung ist aber ungleichmäßig und sie werden gewöhnlich in der dem Dünndarm zugerückten Pankreasgegend nahezu vollkommen vermißt, während im entgegengesetzten Milzende des Pankreas in der Regel außerordentlich große Inseln auftreten. Diese großen Inseln stimmen aber in der histologischen Struktur mit den kleineren überein, so sind sie als kompakte Anhäufungen kleinerer Inseln zu betrachten.
Im Bereich der größeren Ausführungsgänge kommen die Inseln in der Regel kaum vor, es wurde aber aüßerst selten eine kleine Insel aus wenigen Inselzellen innerhalb des einschichtigen Zylinderepithels gefunden.
Zwischen den exokrinen Acinuszellen treten zuweilen vereinzelt Inselzellen auf, welche aber niemals Inseln bilden.
2. An den Inseln von Elaphe quadrivirgata lassen sich drei Arten Inselzellen, A-, B- und D-Zellen in den mit Azan gefärbten Präparaten unterscheiden. Die A- und B-Zellen stellen wesentliche Bauelemente der Schlangeninsel dar, während die D-Zellen als Zustandformen der B-Zellen zu betrachten sind, da sie fast immer außer den blau gefärbten D-Granula noch B-Granula in wechselnder Menge zu führen pflegen und Übergänge zwischen beiden Zellen gefunden werden. Das Vorkommen der D-Zellen in einzelnen Inseln ist ganz unbestimmt.
Bei den Schlangeninseln erreichen nahezu sämtliche Inselzellen mit ihren Apikalenden die Wand der Blutkapillaren, die reichlich das Inselgewebe versorgen. Die Kerne der Inselzellen, welche bei der Schlange in den A- und B-Zellen fast gleich beschaffen sind, liegen gewöhnlich in dem entgegengesetzten Basalabschnitt der Inselzellen. Die spezifischen Granula verteilen sich bei drei Arten Inselzellen in der Cytoplasmazone zwischen dem Kern und dem Apikalende der Zelle, in der sie mehr oder weniger dichte Anhäufung bilden, diese nach der Blutkapillare orientierte Granulaverteilung ist bei den Schlangeninselzellen auffallend deutlich ausgeprägt. Bei den Schlangeninselzellen wird der Befund aber nicht bestätigt

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