Changes in fine structure of rabbit liver cells throughout the embryogenic development are studied on light and electron microscopy with the following results.
1. The liver cell-cords and the bile canalicules of rabbit fetus are formed on and after about the 20th day. The formation of the liver cell-cords is assumed to complete about 20 days after the birth of rabbit. The interlobular connective tissue starts to develop a little later, connective tissues fibres being stained distinctly 25 days after the birth. Then the vascular wall is well formed, the bile canalicules develop and the interlobular veins can be differentiated, so that the GLISSON's capsule is clearly visualized.
2. At the end of the first half period of embryogenesis, there are observed in the liver cells a small number of fat droplets, which increase in number from about 20th day on, reaching the maximum in 27 days. But they rapidly decrease after birth, increase again in several days. Glycogen is detected at the end of embryogenesis. It disappears after birth and then re-appears simultaneously with the apperance of fat. Thus it is understood that fat which has been stored in the embryogenic period supports the rabbit's life for several days after birth. Later, fat and glycogen are produced following lactation.
3. Under the light microscope the mitochondria are, while liver cells are not yet differentiated, fine rod shaped or thread shaped showing no functional feature. Then mitochondria increase in number and are definitely arranged. Simultaneously they enter the fat rich period becoming granular. Fat-rich cells reveal many threadlike mitochondria. But relationship between mitochondria and fat droplets is not so clear as in the liver cells in adult animal. When fat is produced again after birth, mitochondria increase in number, especially granular ones. This suggests a relationship between mitochondria and fat droplets. The suggestion, however, is not so earily verified as in the adult body.
4. Even in their indifferentiated stage, the mitochondria in the liver cells possess limiting membrane and cristae in the electoron microscope. Despite differentiation, the mitochondria show few changes in their inner construction. But duriug the fat-rich period, there appear many intermediacies between the typical mitochondria and the fat droplets. These intermediacies can be traced up to the mitochondria as the origin of the fat dedroplets. When fat is produced after birth, mitochondria are found to increase showing multitudinous structures in cristae. The fact that many constricted figures appear during this multi mitochondria period (increased mitochondria period) suggests an increasing of mitochondria.
5. Hemopoietic figure is already seen in the liver of a rabbit fetus on the 15 day. This initial hemopoiesis is almost of red blood cells, but at the end stage of embryogenesis of white blood cells. Their production disappears in 14 days after the birth.

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The epithelium of the laryngeal side of the epiglottis of flying-squirrel is a stratified flat epithelium much thinner than that on its lingual side, but near its median line, it is a 5-6-rowed ciliatated epithelium. No papillae are formed beneath this stratified flat epithelium, as are found on the lingual side of the epiglottis. Taste-buds are found on the lingual side alone in small number. The mixed glands are well developed in the median and the peripheral parts of the laryngeal side. The epiglottic cartilage is of hyaline nature and forms one integral plate.
The ventriculus laryngis forms a huge laryngeal sac, which reaches the inner surface of the thyroid cartilage on the ventral side, juts out toward the pharyngeal mucous membrane on the dorsal side, reaches the vicinity of the hyoid bone beyond the upper border of the thyroid cartilage on the cranial side and extends down to the upper end of the trachea on the caudal side. The sac is generally lined by a one-rowed cubic epithelium and partly by a 2-rowed cylindrical epithelium. The propria is very ill developed and mixed glands are found only in a limited area.
The vocal cord consists in the main of 2-rowed stratified flat epithelium and a thin propria, but their ventralmost part alone is covered by a 2-3-rowed cylindrical or ciliated epithelium. The ventral one-third of the pars intercartilaginea of the rima glottidis is composed of a 2-rowed flat epithelium and a thin propria, but its dorsal tow-thirds are of a 2-3-rowed ciliated epithelium and subepithelial connective tissue gradually gaining in thickness dorsalwards and containing some mixed glands. The lower part of the larynx between the rima glottidis and the entrance to the trachea is composed of a 2-3-rowed ciliated epithelium and a subepithelial connective tissue layer containing mixed glands.
The laryngeal mucous membrane of flying-squirrel is supplied with sensory fibres as in man, dog, goat and rabbit, but much less abundantly than in these, the submucosal and the proprial plexus found very well developed in these mammals being much inferior in flying-squirrel. The sensory nerve terminations are also much simpler in formation, no such corpuscular terminations or complex branched terminations as found in the above animals being ever to be found here.
The sensory terminations found in the laryngeal mucous membrane of flying-squirrel are of unbranched and simple branched types formed either subepithelially or intraepithelially. Most primitive subepithelial unbranched terminations are found everywhere in the mucous membrane and in the laryngeal sac in particular most of the terminations are of this type, found here and there in sporadic existence. Thus, the sensory supply to the laryngeal sac may be called very poor in general, but near the entrance of the ventriculus laryngis subepithelial and intraepithelial simple branched terminations are not rare either. The terminal fibres of these terminations are sometimes comparatively thick and sometimes run wavy courses.
The laryngeal side of the epiglottis is richest in sensory fibres, rather complex branched ones being found among their terminations, especially near its median line. Branched terminations with several terminal fibres are not rare here and some complex intraepithelial branched terminations are present, but the terminal fibres are usually medium-sized or thin, showing not much change in size. In the peripheral parts of the laryngeal side of the epiglottis, the sensory fibers are fewer and their terminations are simpler, but in these parts, simple brached terminations originating in thick fibres may be observed. Terminations formed by extraordinarily thick fibres, as found in man and rabbit, are never found in flying-squirrel.
Sensory terminations are found on the border part between the laryngeal and the lingual sides of the epiglottis but their number decreases rapidly as we pass over into the lingual side

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The cortex of the suprarenal glands of dog and flying-squirrel, being an epitheliogenetic endocrine organ, was found devoid of fibres of cortical nerves proper. Of course the periaterial plexus send out nerve fibres which enter its parenchyma accompanying the blood capillaries, but these are extremely small in quantity and cannot be called nerves proper to the cortex. So, the greatest majority of the capillaries and cortical cells are free of nerve supply. Therefore, the mechanism occcasioning the secretion from this part may be interpreted as consisting in the seeping out of the secretory granules from the gland cells by pressure of dilation of the blood capillaries.
In dog, the extracapsular connective tissue around the suprarenal gland is rich in fat tissue and contain extracapsular or suprarenal plexus with ganglia of varying size. In the rather thick capsule is formed the intracapsular plexus containing only a very few ganglion cells. In flying-squirrel, however, the capsule as well as the extracapsular tissue is very poorly developed, so that the plexuses in them are also very ill-developed. The ganalion cells in the dog's suprarenal plexus belong either to DOGIEL's Type I or to his Type II; their nerve processes are usually well developed.
The suprarenal glands of these animals contain no ganglion cells in its medulla and in its cortex, unlike in the case of man. Therefore, it seems that the presence of nerve cells in the medulla has little functional significance.
The nerve bundles or fibres originating in the extra- and intracapsular plexus, without sending out branches into the cortex, run through it into the medulla, so that these are the nerves proper to the latter. This medulla lies in the main in the central part of the suprarenal gland in flying-squirrel, but in dog it is otherwise found distributed in a manner suggestive of its embryological development. Medullar cell groups are found in the extra- and intracapsular spaces too, often keeping connect with the medulla at the center. Some medullar cells are found arranged cord-wise along the fibres of the medullar nerves proper running through the cortex.
The medullar nerves proper are not rarely composed of thick fibres only, but usually thin fibres also come into the composition. These nerves proper, unlike those in man, run forth toward the center of the medulla, upon entering it, while sending out irregularly winding finer branches. The nerve fibres here seem to become the fewer, the smaller the animal in body size.
Upon parting from the nerve bundles, the medullar nerve fibres run solitary courses as enormously thick fibres showing peculiar winding and perceptible change in size, while thick branch fibres of the same nature and besides many far thinner terminal fibres showing less change in size are sent out during the courses. These fibres of two types never end freely but always come into mutual anastomosis and form a large nervous network in the medulla. In this network, the thick fibres run peculiar looped or augular courses, so that the size and the shape of its meshes are much variegated, forming rectangles, polygones, rhomboids, ovals, spindle-forms and club-forms of varying size. Besides, quite nondescript meshes are also seen. The reticular formation by the thin fibres is also very peculiar, some very large-sized meshes appearing among the usual small-sized ones.
The nerve fibres running in the medulla are not accompanied by SCHWNN's cells, because the medulla is composed of sympathetic chromaffin paraganglion cells originating in mother cells, the KOHN's so-called accessory cells, from which the sympathetic SCHWANN's cells are also derived, and thus can naturally dispense with SCHWANN's cells.
The above-mentioned enormously thick fibres, besides coming into contact supply to the medullar cells, seem also to effect intracellular supply upon penetrating through these cells.

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1. Es wurde das runde Mutterband aus zwei 8monatigen Frühgeborenen an Serienschnitten untersucht. Das Band wird vom Uterus bis zur Beckenwand immer dicker und wird im Leistenkanal beträchtlich dick, von dem äußeren Leistenring an aber wieder dünner.
2. Die dicken Kollagenfasern finden sich in dem im Ligamentum latum uteri laufenden Abschnitt des Bandes am zahlreichsten. Ihre gesamte Menge, d. h. ihre Dicke×ihrer Zahl, ist am reichlichsten im Leistenkanal.
3. Die elastischen Fasern sind in dem Abschnitt des Bandes im Ligamentum latum uteri am wenigsten zahlreich.
4. Die glatten Muskelfasern sind in dem Abschnitt im Ligamentum latum uteri dünn, im Leistenkanal dicker und im subkutanen Gewebe wieder dünn. Die gesamte Menge der glatten Muskelfasern, d. h. ihre Dicke×ihrer Zahl, nimmt im Laufe des Bandes im Ligamentum latum uteri immer zu, um im Leistenkanal beträchtlich zu werden, und vermindert sich nach dem Austritt in das subkutane Gewebe sehr rasch.

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With respect to the relation between nuclear size and chemical composition of its suspending medium, diameters of the nuclei isolated by the technique of sucrose or glycerol were measured in sucrose or glycerol solution in addition with various concentrations of several cations. Obtained results were summarized as follows.
Nuclear sizes were decreased with addition of cations, and on the control of nuclear size, bivalent cations were further effective than univalent. The nuclear size depended only on the concentration of cations, but did not on that of sucrose. Even if the sucrose was substituted with glycerol, similar results were obtained.
These facts throw a question whether a concept of ‘isotony of cell’ is equally fitted for isolated nuclei.

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Nach der Injektion der aus der Markscheidensubstanz von Nerven erhaltenen Emulsion in die Unterhaut der Maus wurden die zeitlichen Veränderungen der in den Bindegewebszellen aufgenommenen Myelinteilchen bezüglich der Größe und der Färbbarkeit mit lipoidfärbenden Farbstoffen untersucht.
1. Durch die Reize der Emulsioninjektion vermehren sich Fibrohistiocyten und Histiocyten. Die Zahl und Menge der phagocytierten Myelinteilchen steigt am 3. Tage nach der Injektion aufs höchste, danach werden sie durch Verdauung verringert. Im Laufe von 10 Tagen verschwinden die Myelinteilchen.
2. Die Myelinteilchen in den Zellen sind nach 6 Stunden mit schwach basischem Viktoriablau 4R schwach anzufärben, und nach 1 Tag bis zum Verschwinden immer stärker. Sie werden aber mit schwach saurem Irisolechtviolett BBN nach 6 Stunden kaum, nach 1 Tag schwach und erst nach 3 Tagen stark gefärbt. Die stärkere Färbbarkeit von Viktoriablau 4R geht offenbar darauf zurück, daß der Farbstoff außer den Lipoiden auch Eiweißsubstanzen zu färben fähig ist.
3. Sudanschwarz B ist ein schwach saurer Farbstoff und färbt nicht nur Lipoide sondern auch echtes Fett, so daß es von Anfang an bis zum Ende die Myelinteilchen in den Zellen färben kann.
4. Das am schwächsten polare Sudan III färbt Myelinteilchen in den Zellen anfangs stark, aber danach immer schwächer, weil offenbar die Myelinteilchen sich spalten und stärker polar werden.

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The results of my study on the suprarenal glands of early stage human embryo based on their silver-impregnated specimens may be summarized as follows.
In my 20mm embryo, the plexus solaris containing numerous ganglia was found fairly well developed between the cortical body of rather large size and the aorta abdominalis. The sympathicoblasts in these ganglia, however, are round cells far smaller than the cortical cells and packed very closely. Very fine nerve fibres have been discovered amoug the groups of such cells, but their relation to the smypathicoblasts could not be made out with any certainty, for no neurofibrils were formed in the cell bodies and consequently no nerve processes were in formation. Thus, these blastocytes are nothing but uniform and entirely undifferentiated primitive cells. Accordingly, no ganglion cells, mantle cells or SCHWANN's cells are yet born.
Such ganglia of primitive sympathetic cells are formed also on the medial side of the cortical body, out of which the cells immigrate further into the deeper part of the cortical stock. The immigration in this stage of embryonic life is advanced so little that its beginning may be probably set at a time short before this stage.
In my 40mm embryo, the plexus coeliacus and the plexus suprarenalis become better developed and the ZUCKERKANDL's paraganglia also comes into incipient formation. The sympathetic cells in the ganglia of the plexus, however, show as yet no trace of differentiation. Only the nerve fibres running among them come to show strong silver-afffinity.
The immigration from the vicinity of the cortical body into its inner part of the sympathetic cells accompanying nerve fibres is now very perceptible, and some cell groups are detected in sporadic existence in the central part of the body, the small cells in the groups being easily distinguishable from the far larger cortical cells. Such cells of the immgrating hordes sometimes penetrate as far as into the center of the cortical body by this stage, but yet no differention of them into medullar cells or ganglion cells sets in.
The abdominal paraganglia quite identical in nature with the medullar tissue are found in incipient formation within the plexus solaris and around the abdominal aorta. The cells in these paraganglia are rather light large cells and a considerable number of nerve fibres showing more or less frequent change in size are found in these paraganglia.
In my 80mm fetus, the nerve elements in the suprarenal plexus and the adrenal medulla originting therein show a considerably advanced differentiation. In the suprarenal plexus, the ganglion cells begin to send out nerve processes and to show the mutipolarity specific to the sympathetic ganglion cells. The development of such processes, however, is as yet very poor. SCHWANN's cells appear sporadically alongside the nerve fibres, but no mantle cells are yet to be formed around the nerve cells.
In this stage, the suprarenal gland undergoes very interesting changes as follows. The suprarenal medulla enlarges in the central part of the gland, extending over an area somewhat larger than that of the certex in cross-section. The sympathetic cells begin to show differentiation and their suddenly inflated bodies are found containing granules probably showing ohromaffinity, while the cortical cells are reduced into small cells, large cells being found no more. The medullar tiasue comes to contain numerous nerve fibres, of which the terminal mode assimilates that in human adults. Groups of spmpathetic cells as yet utterly undifferentiated may be found here and there in the medullar tissue. These groups later on become the ganglia found in the medullar tissue in all probaility.

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In das Epithel der normalen Wangenschleimhaut der Maus dringen Farbstoffe in folgender Reihenfolge ein: Viktoriablau, Neutralrot>Lackschwarz extra, Irisolechtviolett BBN>Trypanblau. Wenn die Wangenschleimhaut zuvor auf 50°C 10 bis 20 Minuten lang erwärmt ist, so dringen die Farbstoffe beträchtlich leichter in das Epithel ein und gelangen oft durch dieses hindurch bis in das unterliegende Bindegewebe.
Auch die Wand des Ausführungsganges von Speicheldrüsen wird durch das Überwärmen für die Farbstoffe durchläßiger.
Die Erhöhung der Durchläßigkeit der Wangenschleimhaut für Farbstoffe durch Überwärmen gilt wahrscheinlich auch für andere Arzneimittel, Gifte und Viren.

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1. The distributions of alkaline phosphatase in the tooth supporting tissues (paradentium), using the decalcifying sections of the upper and lower molars of the rats ranging from the first day after birth to the stage of maturity, have been investigated histochemically through GOMORI's method.
2. Alkaline phosphatase is distributed through the whole periodontal membrane (Fig. 1, 6 and 7). The enzymatic reactions of the fibroblasts situated in SHARPEY's fibers are intensive in grade in the periodontal membrane, but the reactions of SHARPEY's fibers are themselves lower than those of the fibroblasts (Fig. 2). The enzymatic activities in each element consisting of the periodontal membrane are more intensive in the region adjacent to the alveolar bone, than in all the other regions (Figs. 1, 6, 7, 9, 10 and 11). And, in the regions where new bony matrix is formed actively, in which newly elaborated SHARPEY's fibers are inserted, both SHARPEY's fibers and the fibroblasts, particulary, show intensive reactions on one hand (Fig. 2, 8, 9 and 10). But, on the other hand, the reactions of the periodontal membrane adjcent to the cementum, under normal conditions, are not so intensive. The same is found in both the surface of the cellular cementum (Figs. 1 and 11) and the acellular (fibrous) cementum (Fig. 2), and, further, in the surface of the forming cementum.
The intensity of enzymatic reactions of SHARPEY's fibers and the fibroblasts are different in several portions of periodontal membrane: the fibers of horizontal, transseptal and interradicular fiber groups show higher reactions than in the other fiber groups in the normal condition (Figs. 6, 7, 8, 9 and 10).
3. The reactions of alkaline phosphatase of the cementum consist of those of cementoblasts, cementum matrix and cementum corpuscle (Figs. 3, 4, and 5). The enzymatic activities of cementoblasts are almost similar to their neighbouring fibroblasts (Figs. 1 and 2). There is no difference between the cementoblasts on the surface of cellular cementum and the acellular cementum (fibrous cementum) at all (Figs. 1 and 2).
The enzyme is not found in the matrix of acellular (fibrous) cementum, but it is, occasionally, found moderate at the junction of the cementum and the periodontal membrane, and just a bit in the cemento-dentin junction (Fig. 2).
In the cellular cementum, the newly formed matrix (cementoid) on the superficial layer shows a slight reaction, but this reaction decreases gradually as it reaches deeper layers, and then disappears entirely. The reactions of the cementum corpuscles consist of the reactions of cementocytes and those of the wall and processes of cementum lacuna. Their reactions prove highest in the superficial zone of cementum, and decrease as they go downwards to deeper layers. Several cementum corpuscles neighbouring the cemento-dentin junction, occasionally, show however moderate reactions of the enzyme (Figs. 1, 3, 4 and 5).
4. The reactions of the alveolar bone consist of three kinds of reactions: those, of the osteoblasts, of the bony matrix, and, of the bone corpuscles. By the side of new bone formation, such as the alveolar crest of young rats, the osteoblasts and their surrounding fibers, show very intensive reactions in the enzyme. Newly formed bony matrix and the osteocytes contain a considerable amount of the enzyme, but it gradually decreaes as they run downwards to deeper layers, and disappear in some portions (Figs. 2, 8 and 10). On the surface of the bone which is now not being formed, the fibers and cells of its surrounding connective tissues (periostium) also considerably react. while superficial bony matrix and osteocytes do slightly (Figs. 2, 3 and 4).
The intensity of reactions of the osteoblasts and the bony matrix, and their surrounding fibroblasts and fibers are generally more conspicuous as compared with that of the cementoblasts, the cementum matrix, and their surrounding fibroblasts and fibers

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Mazeriert man ein mit Formalin fixiertes Nervengewebestück mit Karbolsäure und färbt die Schnitte nach der HEIDENHAINschen Eisenhämatoxylinmethode, so können die Nervenzellen und ihre Fortsätze wie auch gewisse Neurogliazellen auf dem entfärbten Hintergrunde schwarzviolett tingiert auftreten.

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