The transitional epithelium and the subjacent lamina propria of the urinary bladders of horse-shoe-bats (Rhinolophus ferrum equinum Nippon) and rabbits (Lepus cuniculus) were observed with the electron microscope.
The epithelium consists of three layers, i.e., the superficial, middle anp basal layers. No microvilli are provided on the free surface of the superficial cells, but many incisures of various depth are observed. In stretched condition of the bladder wall, these incisures are markedly reduced in number and depth. A special layer of apical cytoplasm which contains many small dark granules probably of glycogen and a considerable number of vesicles are occasionally observed in the uppermost part of the superficial cell. This layer corresponds to the crust konwn by light microscopy, and many mitochondria are gathered in a zone just beneath this layer. Many vesicles and vacuoles are characteristically found in the superficial cells, the contents of these are either empty clear or filled with various granular or vesicular particles. According to an experiment that oil emulsion is infused into rabbit bladders, it was proved that vesicles or vacuoles of the superficial cell are capable to engulf the fatty substance contained in urine by a mechanism of the pinocytosis. Water and watersoluble electrolytes may also be absorbed into the epithelium by a similar mechanism. In the cytoplasmic matrix of the superficial cell many bundles of tonofilaments are observed.
In cells of the middle layer, pinocytotic vesicles and fat droplets are also observed, but there is a tendency that they are preferentially gathered at the region just beneath the superficial layer; and none of them are observed in the basal cells. Thus it seems likely that the fat and other ingested substance may be released into the narrow intercellular space at the level of the middle layer, and may pass through the basal layer by the way of intercellular channels. The basal cells are often dark in appearance and contain many small dark granules which are probably identical to the free RNA granules.
Periodically arranged desmosomes in short intervals are seen in the lateral cell boundaries of the superficial layer of the rabbit epithelium. These are thought to produce a useful resistance against stretching. A peculiar complicated folding of plasma membranes at the intercellular boundaries may be related to the remarkable change of cell outlines concerning the stretching and contraction of the bladder wall.
A thin basement membrane borders the epithelium from the underlying lamina propria. The wall of the subepithelial capillary consists of thinly flattened cytoplasm of the endothelium and the basement membrane outside it. Occasional pores are observed through the thin film of endothelial cytoplasm and may be probably related to the transfer of substances absorbed from the bladder lumen.

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Untersuchungen am Zwischenhirn-Hypophysensystem von Elephas maximus, durch Hypothermie ad exitum gekommen, haben ergeben:
1. Die neurosekretonische Bahn wird in ihrer gesamten Ausdehnung von den beiden Kerngebieten im Hypothalamus (Produktionsort) bis in die Neurohypophyse (Stapelort) elektiv hervorgehoben.
2. Der Nucleus paraventricularis imponiert durch die dichte Ballung seiner neurosekretorischen Zellen. Zwischen dem Nucleus paraventricularis und Nucleus supraopticus treten im Bereich großerer Gefäße zahlreiche Streugruppen auf. Der Nucleus supraopticus besteht aus einem dorsolateralen, dorsomedialen und einem ventromedialen Areal neurosekretorischer Zellen.
3. Nahezu alle neurosekreotischen Zellen enthalten Sekretgranula. Teilweise lassen sie sich in die Zellfortsätze verfolgen.
4. Nun im distalen Abschnitt der proximalen Kontaktzone (Infundibulum und Pars infundibularis adenohypophyseos) ist die Anneicherung von Neurosekret deutlich. Spezialgefäße, von den proximalen Endigungen neurosekretorischer Fasern umgeben, sind von Neurosekret umlagert.
5. Die Neurohypophyse ist von neurosekretonischem Material weitgehend frei. Die Befunde an Silberpräparaten sprechen gegen die Auffassung, daß Neurosekret durch den Zerfall (physiologische Degeneration) distaler Axonabschnitte entsteht.

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Bei 10 Fällen von lebendfrischen Bauchhäuten aus geschlachteten Pferden wurden die Schweißdrüsen cytologisch und histologisch eingehend studiert. Kleine Hautstücke wurden mit dem LEVIschen, REGAUDschen und ZENKER-Formol fixiert; für die Darstellung des GOLGIapparates behandelte man sie mit der KOLATCHEVschen Osmiumimprägnationsmethode. Die Mitochondrien der Drüsenzellen sind in den mit dem LEVIschen Gemisch fixierten, mit dem Eisenhämatoxylin nach HEIDENHAIN gefärbten Präparaten gut dargestellt, aber sie sind ebenso in den nach KOLATCHEV behandelten Schnitten nach der vollkommenen Bleichung mittels der KULLschen Anilinfuchsin-Aurantiafärbung häufig sehr prächtig dargestellt. Das Glykogen ist in den mit dem ZENKER-Formol oder REGAUDschen Gemisch fixierten Schnitten mit der Perjodsäure-SCHIFFschen (PAS) Reaktion nachgewiesen; dabei wird in jedem Fall die Speichelverdauungsprobe angestellt, um das Glykogen von anderen PAS-positiven Substanzen zu unterscheiden. Die Sekretgranula der gewöhnlichen Drüsenzellen der Pferdeschweißdrüsen erweisen sich als Speichel-resistent und PAS-positiv. Für die Herstellung der Übersichtspräparate werden die mit dem ZENKER-Formol oder REGAUDschen Gemisch fixierten Schnitte mittels der Hämatoxylin (HANSEN) -Eosinfärbung tingiert. Die fixierten Hautstücke wurden in Paraffin eingebettet, darauf in 4-5μ dicke Serienschnitte zerlegt. Wichtige Ergebnisse werden im folgenden zusammengefasst angegeben.
1. Bei den Schweißdrüsen des Pferdes ist der Drüsentubulus im allgemeinen dünn und das Drüsenlumen eng, so sehen sie häufig den ekkrinen Schweißdrüsen ähnlich, aber ihr kurzer Ausführungsgang mündet ohne Ausnahme in den obersten Abschnitt des Haarbalgs aus, und beteiligt sich niemals an die Knäuelbildung der betreffenden Schweißdrüse. In diesen zwei wichtigen morphologischen Beschaffenheiten stimmen die Pferdeschweißdrüsen mit den apokrinen Schweißdrüsen überein. Bei den Pferdeschweißdrüsen sind das Epithel des Ausführungsgangs und das Myoepithel des Drüsentubulus histologisch und cytologisch ganz gleich beschaffen wie bei den Schweißdrüsen des Menschen und der anderen Säugetiere; in beiden Epithelien werden aber niemals Pigmentgraunla, Fettröpfchen und Glykogen nachgewiesen.
2. Das Drüsenepithel der Schweißdrüse des Pferdes besteht zum größten Teil aus verschieden geformten großen Drüsenzellen, welche immer durch grobe Sekretgranula und -vakuolen ausgefüllt und mit einem auffallend dicken Bürstensaum versehen sind. Diese gewöhnlichen großen Drüsenzellen sind regelmäßig einschichtig angeordnet und besitzen niemals interzelluläre Sekretkanälchen, wie dies bei den apokrinen Schweißdrüsen der Fall ist. Die groben Sekretgranula der gewöhnlichen Drüsenzellen werden im jüngeren Stadium durch Eisenhämatoxylin (HEIDENHAIN) intensiv gefärbt, erweisen sich als Speichel-resistent und PAS-positiv; aber im späteren Stadium wandeln sie sich allmählich infolge der Abnahme der Färbbarkeit in Sekretvakuolen um, deren ganz ungefärbter, PAS-negativer Inhalt die Endstufe des Sekretionsproduktes der Drüsenzellen vertritt. Die Sekretgranula und -vakuolen der Pfedeschweißdrüsen enthalten weder Lipoid noch Pigment.
3. Die gewöhnlichen großen Drüsenzellen führen verhältnismäßig viele stäbchen- und fadenförmgige Mitochondrien, die zwischen den Sekretgranula und -vakuolen nahezu gleichmäßig im ganzen Cytoplasma verteilt sind. Cytologische Befunde, die für die Abstammung der Sekretgranula von den Mitochondrien sprechen

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1. The angioarchitecture of the hypophysial vascular system of five men, fifteen dogs and five cats, has been observed histologically, in comparison with the perfused preparations of the India ink, and various possibilities of blood flow in the hypophysial portal system have been discussed.
2. In some parts from superior hypophysial arteries to the collecting veins through hypophysial portal veins, following elements have been found, which are regarded to participate in regulating the blood flow; a) swelling-cells b) epitheloid muscle cells c) blocking gurdle d) spiral valve e) strangulated veins (‘Drosselsvenen’) f) arterio-venous anastomoses.
3. Adenohpophysis is supplied with blood from superior hypophsial arteries through the portal veins. The venous valves and other several kinds of apparatuses menstioned above are cosidered to make an interruption or reversal of the blood flow in addition to the regulation.
4. The complicated mechanism of regulation of the blood flow in the hypophysial portal system gives an important clue to solve the functional correlation between hypophysis and diencephalon. On this standpoint, all results of previous physiological investigations should be checked again.
5. In the item of discussion, various possibilities as to the direction of the blood flow have been checked under consideration of the apparatuses in various regions of the hypophysial portal system.

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1. The non-enzymatic reduction of tetrazolium salts by SH groups was studied mainly in the keratogenous zone of the hair.
2. The effect of non-enzymatic reduction of tetrazolium salts by SH groups is pH-dependent, beginning at about pH4.4, gradually increasing up to pH7.0 and continuing to increase rapidly thereafter until pH13 which is the highest alkaline pH tested. Addition of diphosphopyridine nucleotide (DPN) intensifies the reaction.
3. It was shown that several inorganic as well as organic substance having SH groups can reduce tetrazolium salts in vitro.
4. It is concluded that the hydrogen of SH groups can be transferred directly to tetrazolium salts in addition to the pathway via specific diaphorases as described by ZIMMERMAN and PEARSE (1959). The main implication of this fact is that the precise histochemical localization of not only coenzyme-linked dehydrogenases but also cytochrome-linked dehydrogenases may be difficult without proper controls for tissue-SH.
5. Since it was found that sodium cyanide higher than 0.01M in the final concentration of the incubation medium can also reduce tetrazolium salts, which may result in the false positive localization of enzymes, the concentration of the sodium cyanide should be kept lower than 0.01M in the incubation medium in the histochemical demonstration of coenzyme-linked dehydrogenases.

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Several male rats aged 80 to 120 days after birth were starved for three days (only drinking water was supplied) and then refed. At 30 minutes, 1, 3, and 5 hours after refeeding, a couple of rats were sacrificed by a blow on the head. Small pieces of gastric wall were fixed in buffered osmium tetroxide and embedded in methacrylate resin. Ultrathin sections were examined under the electron microscope.
1. Body chief cell.
Secretory granules in variety of electron density and size accumulated in the apical cytoplasm of the body chief cell of the starved rats are markedly reduced in number after feeding. As the time elapsed after refeeding, increase in the total area of the GOLGI apparatus, dilatation of the cavities of GLOGI lamellae or vacuoles and enlargement of each GOLGI vesicle may be recognized. Within the GOLGI area may occur several immature secretory granules which are small in size, surrounded by a definite limiting membrane and contains rather dense material. Between somewhat hypertrophied GOLGI vesicles and the immature secretory granules, some intergrades suggestive of mutual transformation may be recognized. As the size of granules increased, electron density of the interior is markedly diminished, and at last they become quite lucent vacuoles with limiting membranes which have been partially ruptured or entirely disappeared.
Rough surfaced endoplasmic reticulum appears in a form of regularly organized parallel lamellae at the infranuclear region of the body chief cell of starved rat, but fragmentation occurs after feeding showing many round or irregular sacs, whose cavities are increasingly densified, being suggested probable accumulation of some material in the rough surfaced cisternae.
It is evident, in the body chief cell, the new formation of secretory granules apparently occurs in the GOLGI area, but the endoplasmic reticulum of rough surfaced type is also actively involved in the synthesis of secretion.
Mitochondria are usually situated in the cell periphery lying along the lateral cell border during the resting stage (starvation), but in the active stage of secretory granule formation they migrate into the vicinity of GOLGI apparatus and often abut against the growing secretory granule, and hence the mitochondria may be also related to the secretory activity of this cell, although none of signs of direct transformation from mitochondria into secretory granules could be observed.
The secretion of this cell may be discharged into the lumen by diffusion through intact plasma membrane.
2. Parietal cell.
The parietal cells in the starved rat are filled with abundant vesicles which are apparently belonged to the smooth surfaced variety of endoplasmic reticulum, and show the intracellular secretory canaliculi whose lumina are totally collapsed in this state. After refeeding the canaliculi are remarkably dilated and smooth surfaced vesicles extremely diminish. After 1-3 hours, the vesicles reappear but small dense particles decrease in number, which are very abundant in the cell immediate after refeeding. It is tentatively assumed that the vesicles of smooth surfaced endoplasmic reticulum probably containing secretory material of this cell may derived from small dense particles.
Presence of GOLGI apparatus in the parietal cell has been doubted by many authors, but in this study poorly developed GOLGI apparatus was rarely seen. The apparatus consists of only vesicles and relatively small vacuoles but does not manifest the so-called lamellae. The mode of secretion discharge by parietal cells may be divided into two, one of which is apocrine type and the other is eccrine. Cytoplasmic projections suggestive of the apocrine extrusion are most frequently observed in the stomach of starved rats.
3. Mucous neck cell.
The mucous neck cell shows no definite alteration in morphology during either fasting or postprandial periods. This cell may not be directly related in function to the digestion

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The composition and the action of the extract which was extracted from the surface region of the hogs' gastric mucosa by ether-alcohol, followed by a further extraction by alcohol have been studied. The results obtained may be summarized as follows.
1. As a result of paper-chromatographic analysis - using n-Butanol + Acetic acid + Water and saturated 10% NH₃ in Butanol as solvent and Ninhydrin reaction-histamine, histidine, tyrosine, methionine and leucine seem to be present in the extract.
2. The subcutaneous injection of the extract into starved rats brings about a remarkable production of secretory granules in the gastric peptic cells. The effects are almost identical with those resulting from the injection of histamine⋅2HCl.
3. The effects of the extract on the contraction of the intestine of guinea pigs (MAGNUS's method) are striking and are very similar to those of 10^-6 histamine⋅2HCl solution.
To sum up the results obtained, we may conclude that though the gastric hormone productin (FUJIE) - which is secreted from the gastric surface cells and promotes the production of secretory granules in the peptic cells and contains an imidazol group - seems to be not a simple component but to be composed of some of amino-acids, the action of productin, however, is so very similar to that of histamine as to suggest that it is merely histamine.

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The major bronchial branches of guinea-pig are smaller in diameter than those of cat, rabbit or hedgehog, containing no bronchial gland or lymphonodule inside the one-rowed cartilages, but the circular bronchial muscularis in their wall is rather well developed, and the epithelium is a rather thick non-ciliated 3-4-rowed cylindrical one. The medium-sized bronchial branches show no essential difference in sturucture from the above, but are more simplified in construction, the cartilages being particularly worse developed, but on the mucosa, regularly arranged low longitudinal mucous folds are found in many places.
In the minor bronchial branches, the muscularis is very thin and the cartilages are only rudimentary, but the mucous folds are still present, covered by a 1- or 2-rowed cylindrical epithelium. The bronchioli respiratorii are composed of a one-rowed low cylindrical epithelium and a thin propria and a small number of smooth muscle fibres are found around them. The alveolar ducts and sacs are of nearly the same structure as in the other animals. It is of interest to find the media of the v. pulmonalis formed of heart muscle tissue, as that of bat. The pleura visceralis also contains a thin heart muscle layer.
The lung of flying-squirrel is far smaller than that of guinea-pig, and accordingly, the bronchial walls are more simply made. The alveoli in the alveolar walls, however, are somewhat larger than in guinea-pig. The major bronchial branches are lined by a 1-2-rowed non-ciliated cylindrical epithelium, and no bronchial glands but not a few lymphonodules are found inside the one-rowed thin cartilaginous pieces. The bronchial muscles here, however, are very poorly developed, being barely found between the cartilages only.
In the medium-sized bronchial branches, the cartilages exist only sporadically, a well-developed circular musculature taking their place. The mucosa is covered by a 1-2-rowed cylindrical epithelium and has a thin propria, containing low mucous folds.
The minor bronchial branches are somewhat simpler in construction than the medium-sized, only a few smooth muscle fibres being fuund around the branches formed of a one-rowed cylindrical epithelium and a very narrow propria. The bronchioli respiratorii with cylindrical or cubic epithelium contain no smooth-muscle fibres. In flying-squrrel too, the media of the v. pulmonalis is of heart-muscle tissue, but the visceral pleura contains neither smooth-muscle nor heart-muscle tissue.
The fundametal or bronchial plexus in guinea-pig is better developed than in flying-squrrel, as may be expected from the above outline of the histological structure. The ganglia accompanying the plexus are especially well developed in the former. The ganglion cells are of sympathetic nature, but in some cases, their multipolarity is very far from apparent, especially in flying-squirrel. In guinea-pig, submucosal plexus derived from the fundamental plexus is also formed in the major bronchial branches, but in flying-squirrel, such a formation is at best very indefinitely observable. The bronchial plexus is composed of many fine vegetative fibres and a far smaller number of thick medullated sensory fibres. Most of the former end in terminal reticula in the bronchial muscularis, but a small part come into relation with the perivascular plexus and partake in the formation of the terminal reticula in the vascular walls.
Some of the sensory fibres are comparatively fine, but some are thick enough, and even enormously thick ones are not rare in the bronchial branches of flyingsquirrel, though very scarce in those of guinea-pig.
Peculiar branched sensory terminations probably concerned with the blood-pressure falling reflex found in the respiratory musculature are present also in the major and medium-sized bronchial branches with rather well-developed muscularis of guinea-pig. These are here, however, of very simple type.

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