The fine structure of the mucous epithelium of the respiratory region of the canine nasal cavity was characterized through the use of the electron microscope. The surface epithelium can be classified as pseudostratified ciliated columnar type composed of ciliated cells, goblet cells, brush cells, basal cells and basement membrane.
The ciliated cell possessed cilia which were approximately 5.5μ long and 0.2μ wide, and intercilialy microvilli which measured 1.5μ in length and 80mμ in width on its free border, and the microvilli were bifurcated sometimes. The cilia contained nine pairs of peripherally arranged longitudinal tubules and one central pair. At the tip of the cilia nine peripheral pairs transformed into nine singlets. At the base of the cilia there were a basal body, a basal foot and a rootlet fiber ended in a granular zone.
The goblet cells were classified to three types according to the amount of mucous droplets. They were a stout goblet cell filled with numerous droplets, one that possesses several mucous droplets, and thin one without a mucous droplet at all. All of them were characterized by their electron opaque features and thick population of the endoplasmic reticulum and other cell organelles.
The brush cell was characterized by its short, relatively uniform filiform projections from the free cell border. The filiform projections resemble the striated border of the intestine.
The basal cells in contact with the basenment memcrane did not reach the free surface, they were asteroid with numerous protoplasmic projections. Also the cells of intermediate height had no free surface. Both the intermediate and low cells were electron opaque.
The basement membrane was rather homogeneous, structureless, electron medium opaque membrane which possessed semidesmosomes.
Acknowledgment. The authors wish to express their appreciation to Dr. A. F. WEBER, Director cf the Department of Veterinary Anatomy, College of Veterinary Medicine, University of Minnesota for the critical advice to investigate the nasal mucous membrane of the respiratory region from the view point of comparison with the olfactory region. Lt. Colonel J. F. METZGER and Major C. O. BURDICK, in the 406th Medical Laboratory, US Army Medical Command in Japan, made available excellent space and facilities for the electron microscopic work, and the generous technical assistance of Mr. MITSUHASHI and Mr. YAJIMA has greatly facilitated the study. Also the authors are grateful to Major R. J. WARNE and Miss NAKAMURA for their assistance in the preparation of this manuscript. Dean OMORI, Prof. KIMATA and Prof. KUWABARA of the College of Agriculture and Veterinary Medicine, Nihon University gave generous considerations for accomplishment of this study. These aids are gratefully acknowledged.

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The fine structure of the intestinal epithelium in the swell fish (Spheroides stictonotus) was studied by electron microscopy in materials fixed in buffered osmic acid and embedded in Epon epoxy resin. Three types of cells can be distinguished in the epithelium.
1. Columnar cells with a striated border are most numerous and common throughout the entire midgut. The luminal surface of the columnar epithelial cell is tightly packed with regular microvilli. In a few places the intermicrovillous plasma membranes are invaginated into the terminal web, giving rise to numerous furrows or a variety of vesicles in the apical cytoplasm. The lateral plasma membranes do not show complex interdigitations between neighboring cells, but desmosomes occur here sporadically. Particular concentration of mitochondria is observed both in the apical and basal cytoplasm of the columnar epithelial cell.
2. The most striking feature in the columnar epithelial cells is the occurrence of endoplasmic lamellar structures which are found mainly infra-nuclear regions. These structures are composed of two very regular, parallel membranes which are separted by a distance of about 250Å. From this characteristic appearance, they are readily distinguished from the usual endoplasmic reticulum. In cross sections, the cavity of these lamellae often shows continuity with the intercellular space. These membranes are never seen associated with RNP particles. These lamellae are independent of each other, being never anastmosed.
3. Typical goblet cells, which are basically the same in structure as those found in other vertebrates, are encountered among columnar epithelial cells.
4. A few of granular cells are occasionally observed singly in the epithelium. These cells contain large granules bounded by a single membrane, aboundant glycogen particles, and a variety of vesicles and tubules. Since these cells do not show any desmosomes between adjacent epithelia, and a similar type of cell is recognized in the lamina propria mucosae, they may be migratory in nature.
5. The present study demonstrates the fine structure of the intestinal epithelium in a marine teleost. Of particular interest is the existence of lamellar structures which have been reported so far only in fresh water fishes. From the observations in fresh water teleosts and in the present study, it is strongly suggested that these lamellar structures are in general characteristic of the fish intestine, even though not in all species of fishes. These structures are assumed to be involved in the mechanism of concentration of salts or of water transport, probably the latter.

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The chemical colour reactions were employed on the sections of the rats' intestines fixed by formalin liquid and embedded in paraffin, using the histochemical methods, and the secretory granules in the PANETH cells were observed.
No positive results were obtained from the biuret reaction (reacts positively to protein, polypeptide) and the COLE aldehyde reaction (the indol group). The xanthoproteic reaction (the phenol group, the phenyl group or the indol group) seems to give a positive colour, but it is so light that the result can not be determined whether+or-. The positive colour or the light positive colour was observed in the ninhydrin reaction (the amino group), the PAULY diazo reaction (the phenol group or the imidazol group), the HANKE-KOESSLER reaction (the phenol group: pink, the imidazol group: yellow). the NILLON reaction (the phenol group) and the PEARSE reaction (S-S, S-H group). The coupled tetrazonium reaction (the phenol, the indol or the imidazol groups) and the pretreatment by 2, 4-DNFB (blocks the phenol group from the tetrazonium reaction) for 16-24 hrs. or by the performic acid (blocks the indol group) give an obvious positive colour. The pretreatment by benzoyl chloride (blocks the phenol, the indol and the imidazol groups) for 48 hrs. gives no positive colour.
By the PAS reaction and the saliva test, the carbohydrates not digested by saliva were proved to exist.
No positive colour was seen in the clear vacuoles (corona) surrounding the granules or in the secretory vacuoles.
To sum up these results, the secretory granules in the PANETH cells seem to be composed, at least, of tyrosine, histidine, cystine (cysteine) and some portion of carbohydrate.

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1. In kombinierter Anwendung von sauren Farbstoffen verschiedener Molekulargröße, z. B. von Anilinblau und Orange G, wurde es färberisch nachgewiesen, daß die Gefügelücken der Ordinärreisstärke, welche bekanntlich zum erheblichen Teil aus nicht oder wenig verzweigten Amylosenmolekülen bestehen, größer sind als diejenigen der Klebreisstärke, welche im Gegensatz zu diesen zum größten Teil von stark verzweigten Amylopectinmolekülen gebildet sind. Dieser Gefügelückenunterschied wäre vielleicht ein wichtiger Grund dafür, daß die Ordinärreisstärke sich mit Jod-Jodkaliumlösung bläulich färbt, dagegen die Klebreisstärke bräunlichgelb, denn das Entstehen der blau erscheinenden größeren Jodaggregate in der Stärke ist nur dann möglich, wenn die sie faßenden Gefügelücken der Särke hinreichend groß sind.
2. Der Größenunterschied der molekularen Gefügelücken in der Ordinär- und Klebreisstärke läßt sich auch in kombinierter Anwendung von mittelstark polaren, spritlöslichen sauren Farbstoffen, wie Irisolechtscharlach B und Irisolechtblau BL, wie auch Irisolechtviolett BBN und Irisolechtscharlach B und ferner Alkaliblau und Eosin, spritlöslich, erkennen.
3. Es ist also gelungen, nicht nur wie vorher die Größe der inter- sondern auch die der intramolekularen Gefügelücken auf färberischem Wege zu schätzen, und zwar an makromolekularen Stärkekörnern.

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