主としてアカガエルの尾芽期初期胚から変態期を経て成蛙に至るまでの真皮原基, ならびに真皮の膜状標本, 乃至はすりつぶし標本を用い, 電子顕微鏡的に膠原線維の発生, 形成過程を追求した.
1. 尾芽期初期胚に於てすでに表皮層と中胚葉層の間に極く薄い透明な膜状基質の存在を認め, この層が成蛙の真皮へと発達する.
2. この薄膜中に細胞と形態的に直接の関係なく, 70-100Åの微細顆粒が多数出現し, やがて一定方向に約210Åの間隔で2列に格子状に排列することをもって, 前膠原線維の形成がはじまる.
3. 顆粒が2列に格子状の排列をとっているこの原線維は隣接の原線維と, 同一格子排列をとるように接着, 重合をくりかえし, また顆粒の大きさの増加もあり, 太い線維へ発達して来るが, 格子間隔は210Åである.
4. これは比較的弱い拡大では210Åの間隔の横紋として認められる.
5. 外鰓末期から内鰓初期にかけて線維形成は特徴的変化を示し, 重合により太さを増した線維の一部に530-640Åの太い横紋の発現を認める. この太い横紋は顆粒の増大とこの顆粒間をつらねる比較的小顆粒の発現などにより, 一定部位の蛋白分子間の結合が特に密になるために生ずるもののようである.
6. 顆粒を重合, 接着せしめる材料は想像の域を出ないが, glycoprotein, tyrosine, hyaluronic acid 等が考えられる. また分子間の荷電の問題もあるであろう.
7. 成蛙の線維は完全に膠原の特色を示す640Åの横紋と, その間に約5本の細い縞を認めるが, さらに一部に明らかに格子排列を見ることができた. この所見は, 初期の線維出現のときから各時期を通じて一貫したものであり, 線維蛋白分子の性質とその重合, 発達過程を電子顕微鏡的に示したものといえる.

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水平は歯牙の不染研磨標本を位相差顕微鏡で観察中, 偶々, 象牙細管の側枝の末梢附近に球状の構造物のあることを見出した.
この構造物が光学的偽像, 或いはその他の原因によってこの様に見えるものか, 正常の構造物であるかを決定する為に組織化学的検索を加味して研究を行った.
ヘマトキシリン染色, Mallory 染色等の普通染色では, 象牙細管壁に強い親和性のある色素のみが球状構造を現出し得る.
結晶度の低いカルシウム塩の組織化学的証明法である Kossa 法, 或いはアリザリン-レッド-S法で球状構造が明らかとなるので, この部分は石灰化が遅れて結晶度が低いものから成立っている構造であることが明らかである.
脱灰切片に就いてはわれわれが行った如何なる染色法によっても球状構造は証明出来なかった. 従って球状構造の部分の有機性基質に変化があることは証明し得なかったが, 固定法, 脱灰法の改善によって染色が可能であるかも知れない.
ズダンブラックB法によって球状構造は著明に現出し得る. この事は脂肪性要素の多い象牙線維との間に何等かの物質交流があり得ることを示す.
以上の諸点より象牙細管の側枝の末梢にある球状構造物が象牙質の代謝に何等かの役割を果しているであろうことが推察せられた.

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In der vorliegenden Untersuchung wurden die Lebern aus 39 zwei- bis zehnmonatigen Menschenfoeten histologisch und cytologisch beobachtet, um die Entwicklung der von ITO entdeckten Fettspeicherungszellen in Sinusoidwand sowie der KUPFFERschen Sternzellen, die Histogenese des Lebergewebes, die Hämatopoese in embryonalen Lebern, ferner den Fett- sowie den Glykogengehalt des foetalen Lebergewebes und die Mitochondrien der foetalen Leberzellen genauer zu studieren.
Am Beginn des 2. Foetalmonates zeigt das Lebergewebe eine lockere spongiöse Struktur mit weiten Sinusoiden, die sich nach dem 3. Foetalmonat vollkommen in eine dichte Netzsturuktur mit engen Sinusoiden umwandelt. Diese eine netzartige Struktur bildenden dicken Leberzellenstränge stellen sogar am Foetalende keinen radiären Verlauf dar; sie verdünnen sich zwar mit dem Fortschreiten der Foetalmonate nach und nach, doch findet man selbst am Ende des Foetallebens keine aus in einer Reihe angeordneten Leberzellen bestehenden Leberzellenstränge.
Gallenkapillare kommen schon im 2. Embryonalmonate vor, sie besitzen im allgemeinen verhältnismäßig weite Lichtungen, welche aber von dem 3. Monate an so eng wie bei Erwachsenen werden. Im ganzen Foetalleben sind die Gallenkapillare von vielen, radiär angeordneten Leberzellen umgeben und auf Querschnitten der Leberzellenstränge stellen sie eine dem Endstück der tubulösen Drüse ähnliche Struktur dar. Die Zahl der die Gallenkapillarlichtung umgebenden Leberzellen vermindert sich in späteren Foetalmonaten, aber die der tubulösen Drüse ähnliche Struktur verschwindet selbst im Endstadium des Foetallebens nicht vollständig. Im 2. bis 4. Foetalmonate kommen im Leberparenchym nicht selten dem Gallengang ähnliche Strukturen in beträchtlicher Zahl vor, bei denen viele niedrigen Leberzellen eine weite Lichtung umschließen, welche zweifelsohne der Gallenkapillarlichtung entspechen soll. Die oben erwähnten speziellen Bauverhältnisse der embryonalen Gallenkapillaren sind auf den dicken Leberzellenstrang der embryonalen Leber zurückgeführt, der aus mehrreihig angeordneten Leberzellen zusammengesetzt ist.
Gleichzeitig mit dem Auftreten der GLISSONschen Scheide im 3. Foetalmonate wird die sichere Unterscheidung der Pfortaderäste von den Vv. centrales möglich; mit dem Fortschreiten der Foetalmonate nimmt das Bindegewebe der GLISSONschen Scheide an Menge zu, in dem sich im 5. Foetalmonate die Bindegewebsfasern deutlich vermehren. Im 4. Monate lassen sich die Leberarterienäste durch das Vorkommen der Myoblasten in ihrer Wand mit Sicherheit unterscheiden.
Die Bildung der interlobulären Gallengänge tritt im 3. Monate, also gleichzeitig mit dem ersten Zustandekommen der GLISSONschen Scheide angrenzend an die Oberfläche des Leberparenchyms ein. Die kubischen Epithelzellen differenzieren sich von den Leberzellen, bilden zuerst in der Lage der Zwischenstücke Halbkanäle mit weiten Lichtungen, deren Wandung zum Teil aus dem Leberzellenstrang selbst besteht. Die vollständig ausgebildeten Gallengänge kommen erst im 5. Monate vor. Sie sind allseitig vom Bindegewebe der GLISSONschen Scheide umschlossen.
Die Leberzellen sind in früheren Embryonalstadien klein und dunkel, mit je einem relativ größeren Kern versehen, sie wachsen mit dem Fortschreiten der Foetalmonate nach und nach und werden mit der Zunahme des Glykogengehaltes hell, aber sie erreichen sogar im Endstadium des Foetallebens die Größe der Lebrezellen von Erwachsenen nicht. Die Mitose der Leberzellen ist im 2. Foetalmonate am zahlreichsten aufzufinden, sie reduziert sich allmählich in den anschließenden Foetalmonaten und wird im 7. Monate sehr gering. Die zweikernigen Leberzellen erscheinen zum ersten Mal im 6. Monate, nehmen in den folgenden Monaten an Zahl zu.

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A histogenetic study was done on the anterior pituitary of rats of both sexes progressing in age from birth to maturity. The results obtained were as follows:
1. The parenchymatous cells of the rat anterior pituitary were composed essentially of chromophobe, acidophile and basophile cells. Two distinct cell types of basophils (delta- and beta-cells) could be distinguished by the application of the periodic acid-SCHIFF technique and GOMORI's aldehyde-fuchsin method.
2. Chromophobes were generally small in size and contained fine filamentous material but no coarse secretion granules in the cytoplasm. Their cell boundaries were not as clearly defined as in the chromophils. The nuclei of chromophobes, round or oval in shape, contained relatively few chromatin particles and usually one or two acidophilic nucleoli. These cytological characteristics indicate that the chromophobes are in an undifferentiated state.
3. Acidophils, though not as abundant as in adults, could already be identified by the presence of acidophilic granules in the cytoplasm immediately after birth. Acidophils were frequently observed to contain negative images of the Golgi apparatus in juxta-nuclear regions as cap-like figures and basophilic filamentous materials suggesting the presence of ribonucleic acid. As the animals approached maturity acidophils gradually became densely packed with cytoplasmic granules. On the whole there was a greater increase in the number of acidophils during growth and development of females than in males, therefore the number of acidophils in adult females exceeded that in males.
4. Beta-cells characterized by the presence of cytoplasmic granules which react positively with the PAS reagent and aldehyde-fuchsin showed well-defined but irregularly shaped cell boundaries. These cells could be recognized from the earliest post-natal period. Their cytoplasmic granules gradually increased with age. In adult females most basophils were beta-cells, while in adult males delta-cells were predominant.
5. Delta-cells were large in size, oval or round in shape, and had distinct cell boundaries. Their fine cytoplasmic granules which react positively with the PAS reagent and aldehyde-fuchsin were distributed throughout the cytoplasm except in the GOLGI area. Some of these cells were densely granulated especially in the peripheral zone of the cytoplasm. The negative image of the GOLGI apparatus of delta-cells was seen in the juxta-nuclear region as a clear, granule-free, circular area with a red centrum by the PAS technique or a dark blue centrum by the azan stain modified by MARTINS. In adult males, delta-cells were frequently found in the ventral area of the anterior lobe and the upper region adjacent to RATHKE's residual cleft. In adult females, on the other hand, delta-cells which were smaller in size and less granulated than those of adult males were located in the central region of the anterior lobe. In addition, most basophils of adult females were not delta-cells, but beta-cells.
6. During the earliest postnatal life, delta-cells were scarce in number, small in size and showed feeble stainability for various dyes. In males, they became numerous and more densely granulated towards maturity. On the other hand, in females, they attained the maximum number on the 30th day, and decreased rapidly thereafter.
7. Between the 35th and 45th day a remarkable change took place in deltacells of the females. During this period degranulation of delta-cells was observed. In addition, the majority of degranulated delta-cells was small in size when compared with delta-cells of the previous stage and had pycnotic nuclei, although delta-cells of the 30-day old female were similar in cytological details to those of males at the same age.
8. According to PURVES and GRIESBACH (1954, 1955) and SIPERSTEIN, NICHOLS. GRIESBACH and CHAIKOFF (1954), two specific types of delta-cells were distinguishable in the rat anterior pituitary.

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The colloid secretion into the thyroid follicular lumen of non-treated and adrenalin-injected domestic fowls was observed in electron microscope.
Mostly in the basal part of the follicular cell of thyroid, it is noticed the striking group of sacs of endoplasmic reticula which are filled with homogeneous material similar to the colloid in the follicular lumen. These sacs, increasing their size, come near the free surface of the cell. Thereafter, in some cases, the enlarged sacs are broken at the surfaces of the follicular cell and evacuate their contents into the follicular lumen; and in another cases, the several sacs with fragments of cell membrane and of cytoplasma, being teared off from the cell, fall into the follicular lumen in which the colloidal content flows out through the destruction of the sacs.
After these observations it is concluded that the secretion of the thyroidal colloid into the follicular lumen is of apocrine type.

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The eccrine sweat gland located in the subcutaneous tissue at the palmar side of carpal or metacarpal regions of forelegs of the pig (the carpal organ) was studied with the electron microscope. Besides the description of its fine structures, dicussions on the secretion mechanism of this gland are presented in this paper. The results obtained are summarized as follows.
1. Two different cell types of the glandular epithelium which were previously pointed out by light microscopy (KITAMURA, 1957), namely the dark and clear cell, are clealy distinguished from each other under the electron microscope. The designation of two cell types may depend on the previous light microscopic observation, though appearances by light- and electron microscopy may often be reverse.
2. Within the cytoplasm of the dark cell, there exist a great number of secretory granules or vacuoles. The electron density of these granules or vacuoles is so low that the electron optical appearance of this cell type is rather clear, in contrast to the image by light microscopy of stained preparations, in which the secretory granules are always darkly tinted. The secretory granule is surrounded by a dense smooth membrane (probably one type of the smooth surfaced variety of the endoplasmic reticulum). As it grows and ripens, its internal substance shows a marked decrease in density and the fusing of neighbouring granules occurs, then it converts into the secretory vacuole.
3. A small number of mitochondria with high electron density are present in the dark cell cytoplasm. The rough surfaced variety of the endoplasmic reticulum is occasionally observed to be localized at the infranuclear zone. Furthermore, small dense particles (microsomes) and microvesicles are abundant within the cytoplasm, especially in the interstices among the secretory grauules. It was forcibly convinced from many electron micrographs that granules of varying sizes and densities might be transitional forms from one to another of each of the microsomes, microvesicles, secretory granules and secretory vacuoles.
The GOLGI apparatus consists of GOLGI vesicles, several pairs of GOLGI membranes and GOLGI vacuoles, which are probably produced either by the expantion of GOLGI vesicles or by the terminal vacuolation of flattened sacs, viz. GOLGI double membranes. It is difficult, in some cases, to distinguish the GOLGI vacuole from the secretory granules.
4. The secretory granules of the clear cell are generally opaque to the electron beam and are small in number. These often situate in the vicinity of the crescent-shaped endoplasmic reticulum (rough surfaced). Somtimes, extremely dense granules with irregular outline were observed; they might be identified as fat droplets.
5. As compared with the dark cell, far more numerous mitochondria are contained in the clear cell. They have marked limiting membranes and internal ridges (cristae mitochondriales), both of which are electron dense and show a double membraned structure. There have been recognized various transitional steps from the mitochondria to the secretory granules of the clear cell.
6. In the clear cell cytoplasm, were observed to be scattered many microsomes and thread-like or tubular structures. The latter may be considered to be produced by chaining of microsomes, and sometimes they aggregate in a compact mass of peculiar crescent shape, which is found to surround the nucleus at the supra- and paranuclear sides maintaining a roughly uniform distance apart the nucleus. This crescent-shaped structure was found under the ordinary light microscope to be strongly basophilic. The constituent elements of such a crescent-shaped mass possess the characteristic of typical endoplasmic reticulum (rough surfaced); but in the case that thread-like or tubular structures are dispersed throughout the cytoplasm, the characteristics of the endoplasmic reticulum are obscure in such distributed bodies.

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猿口唇も人の場合と同様, 外皮部, 移行部及び粘膜部に分れられ, 移行部は更に外帯と内帯に区別される. 外皮部は洞髪所有の一般有毛性外皮で表わされる. 移行部外帯の上皮は外皮部の表皮よりも遙かに厚く, 之に対する固有膜からの乳頭形成も著明で此部は粘膜性を示す. 然し一方この部は毛髪をも所有するから同時に外皮性を示す. 移行部内帯の上皮は一層厚く, 又乳頭形成もより強力で, この部には毛髪は見られない. 粘膜部では上皮の発達は良好であるが, 乳頭は狭小である.
猿口唇移行部及び粘膜部の知覚神経分布も人の場合と同様, 乳頭の発達と平行的関係を示す. 即ち知覚線維の発達は乳頭の最強力な移行部内帯で最良好, 上皮の発達稍々劣勢ではあるが, 乳頭の発達良好な移行部外帯之に次ぎ, 厚い上皮にも拘らず, 狭小な乳頭所有の粘膜部に於て最劣勢を示す.
外帯の固有膜, 特に乳頭内に形成される知覚終末には次の種類が区別される. 1. 非分岐性及び分岐性終末. 後者は一般に単純性で表わされるが, 稀ならず複雑性を示す. 終末枝は屡々上皮内線維に移行する. 2. 特殊非分岐性及び分岐性終末. 終末枝が肥厚を示し, 強い〓曲走行の後純状に終る特性を有す. 3. 糸毬状終末. 之は屡々 Meissner 氏触小体類似の線維配列を示す. 4. Meissner 氏触小体. 之は外帯の内帯寄りに発見される.
内帯に於ける知覚終末の発達は特に良好, 殊に Meissner 氏触小体に於て然りである. 非分岐性及び分岐性知覚終末も一般に太い線維に由来し, その終末枝は屡々膨隆して終る. 但し上皮内線維は少量に発見されるに過ぎない.
粘膜部では知覚線維も急激に減少し, その終末は専ら非分岐性及び単純性分岐性終末から成り, 小体様終末も上皮内線維もここでは見られない.

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