1. Die Linsenfasern der Cyclostomen sind weder mit "Protoplasmafortsätzen" noch mit "Protoplasma-Stacheln" versehen. Daher verlaufen die Grenzlinien benachbarter Fasern annähernd geradlinig.
2. Bei den Chondrichthyes besitzen die Linsenfasern Protoplasma-Stacheln und verzahnen sich damit. Die Anordnung der Stacheln ist sehr unregelmäßig.
3. Bei den Osteichthyes sind die Linsenfasern mit schön angeordneten Protoplasmafortsätzen und Stacheln ausgerüstet und durch sie fest verbunden. Die Verbindungsart der Protoplasmastacheln entspricht jener beim Rinderauge.
4. Die morphologische Veränderung der Fortsätze und Stacheln der Fasern schreiten von der Oberfläche der Linse nach dem Zentrum allmählich fort. Wenn auch ein konzentrisch lamellärer Bau der Linse im Spaltlampenbilde sowie im polarisationsoptischen Bilde deutlich hervortritt, werden die Klüfte (Spalte), an denen die auffallende Veränderung der Protoplasmafortsätze und Stacheln auftritt, gar nicht beobachtet.
5. Bei der Präparation für das Raster-Elektronenmikroskop wurde ein neues Verfahren versucht: Eine Linse, die vorher in aufsteigender Alkoholreihe entwässert worden war, ließ sich statt der Lufttrockung mit Glyzerin durchtränken. Dadurch wurde die Zusammenziehung des Materials im Hochvacuum vermieden, denn Glyzerin verdunstet schwer.

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The normal human conjunctiva of the upper tarsal region and that affected by vernal conjunctivitis (untreated and hydrocortisone-treated) were observed with the electron microscope.
1. The conjunctiva is lined with stratified columnar epithelium consisting of 2 to 3 layers of epithelial cells intermingled with a few goblet cells. The epithelial surface has considerably deep depressions which are called crypts or intracellular ductules.
2. The epithelial cells show elaboration of small secretory granules of variable electron density in the cisternae of the Golgi apparatus. The granules are gathered around the crypts or ductules and discharge their contents through a small opening formed at the point of fusion between the limiting membrane of the granule and the surface plasma membrane. Such secretory activity of ordinary epithelial cells was accelerated in vernal conjunctivitis.
3. Fine filaments which are abundant in the cytoplasmic matrix of the epithelial cells disappear in the cells of conjunctiva affected by vernal conjunctivitis. They reappear after treatment with hydrocortisone.
4. The lamina propria of the conjunctiva is connective tissue rich in blood vessels and myelinated and unmyelinated nerve fibers. When the tissue is affected by vernal conjunctivitis, fine filamentous material may appear in the matrix either aggregated to form a large mass or infiltrating among collagen fibrils. These developments are considered the counterpart of hyaline degeneration seen with the light microscope as a peculiar characteristic of vernal conjunctivitis. Such a filamentous substance also accumulates in the intercellular spaces of the epithelium which widen as one of the pathological changes of vernal conjunctivitis.
5. Various kinds of mesenchymal wandering cells occur especially in the lamina propria, but some of them infiltrate into the epithelial layer. Histiocytes, eosinophils, neutrophils, plasma cells and mast cells were recognized.
6. Some plasma cells contained globules (Russell bodies) and crystalloids in the rough endoplasmic reticulum. The mast cell granules are highly variable in structure, viz., fingerprint-like, homogeneous, fine granulated or reticular. Mast cells having fine granulated or homogeneous granules are presumably ready to release histamine. These findings on the plasma cells and mast cells point out the allergic inflammation in the conjunctival interstitium.

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Electron microscopic studies were made on the parafollicular cells of the thyroids of normal, vitamin D plus CaCl₂-injected, and CaCl₂-injected mice.
1. The cytoplasmic granules of 200mμ diameter are reduced in number in the animals treated with vitamin D plus CaCl₂ everyday for 2 or 7 days. In these animals the Golgi field is enlarged containing numerous small vesicles and newly formed small granules, suggesting an active granule formation there.
2. No marked changes were observed in the parafollicular cells of the animals given CaCl₂ everyday for 15 or 75 days.
3. The parafollicular cells remarkably reacting to the long-term hypercalcemia seem to be related to thyrocalcitonin production. Their granules are thought to be formed in the rough endoplasmic reticulum and Golgi apparatus system as in other protein secreting cells.

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In specimens taken from albino and black mice, the dog and a human fetus, the Merkel cell, a tactile receptor in the epidermis, and its associated nerve fibers were studied with the electron microscope.
1. The Merkel cell, situated in the stratum basale or the deep part of the stratum spinosum of the epidermis, is lens-like or elliptical in shape orienting its long axis either perpendicular or parallel to the plane of the dermoepidermal junction. The nucleus is always deeply indented with its long axis parallel to that of the cell.
2. The Merkel cell contains many specific granules 700-1000Å in diameter. The electron density of these granules is variable and some of them look like empty vesicles. The specific granules are produced in the Golgi apparatus and greatly accumulate in the cytoplasmic area facing the nerve ending.
3. The specific granules of the Merkel cell may contain a transmitter substance which may be released from the cell through the mechanism of diacrine secretion to stimulate the nerve ending to initiate the impulse of tactile sensation.
4. In the deeply pigmented snout skin of the dog the Merkel cells contain melanosomes, which may have been taken up by the Merkel cell as do the keratinocytes.
5. The Merkel cell is provided with desmosomes on the cell surface adjoining the keratinocytes but not the nerve fibers. The fine structure of the desmosome on the Merkel cell is not different from those appearing between the keratinocytes. The presence of desmosomes suggests that the Merkel cells may differentiate from undifferentiated basal epidermal cells as a result of innervation by afferent nerve fibers.
6. Nerve fibers and endings associated with the Merkel cell contain a large number of mitochondria. Though they are in a close contact with the Merkel cell, there is no plasma membrane specialization such as desmosomes. A few synaptic vesicles in these afferent endings are considered to be possibly related to the induction of differentiation of the epithelial cell into the sensory cell.

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The otic and pterygopalatine ganglia and, as controls, the superior cervical ganglia of the dog were studied by the histochemical fluorescence methed of FALCK and HILLARP.
Most nerve cells of the superior cervical ganglion contained monoamine specific fluorescent granules, and numerous monoaminergic terminals occurred among and around the neurons. There were, however, found neither adrenergic neurons nor adrenergic teminals in both the otic and the pterygopalatine ganglia in normal and even in nialamide-treated animals. A yellow-brown fluorescence of unknown nature, which did not disappear after the administration of reserpine as well as after cervical and upper thoracic sympathetic ganglionectomy, was found in the perikarya of nerve cells in these ganglia.
The findings obtained suggest that there is no adrenergic neuron in both the otic and the pterygopalatine ganglia, and that sympathetic fibers originating from the sympathetic trunk do not make neuron exchange in the two ganglia.

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A celluloid plate dotted with a drop of amyl acetate was pressed to the skin. The impression thus obtained was coated with carbon and gold and observed under the scanning electron microscope. The cellular and subcellular structure of the skin surface could be clearly observed. The wide applicability of this simple method to dermatological and other studies was suggested.

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