A STUDY ON THE DEVELOPMENT OF THE SWEAT GLANDS OF THE CATTLE EMBRYOS

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1. We have studied on the sweat glands on the six parts of the cattle embryo, from the developmental and histogenetic points of view; namely, the fore-head, breast, abdomen, hypogastrium, back and sole (hairly portion) of the cattle fetus from the beginning of the third fetal month to the end of the eighth.2. The sweat glands on the cattle embryos secondarily arise from the hair bases and belong to the apocrine sweat glands. Moreover they are “monoptische Drüsen.”3. The primordia of the sweat glands originate in the middle of the fourth fetal month for the first time and it is in correspondence to the stage of the “Haarzapfen” in the hair bases.4. The regions where the sweat glands spring up for the first time are fore-head and sole. The abdominal part follows next.5. As compared with the sole and the forehead both of which give rise to the first primordia of the sweat glands, a few best developed primordia of the sweat glands occur on the forehead, while on the sole many primordia which are later in development than those on the forehead are perceptible.6. One hair base gives rise to only one primordia of the sweat gland in any region of the body. That is to say, one hair base does not give rise to two or more primordia of the sweat glands in any parts of the body.7. The papillary primordia of the sweat glands are still recognizable on the breast and hypogastrium of the cattle embryo in the beginning of the fifth fetal month, but not recognizable after then. The clavate primordia of the sweat glands are numerously recognizable in every part of the fetal body in the middle of the sixth fetal month but none in the beginning of the seventh fetal month.8. The bending at the apex of the primordia of the sweat glands was recognized for the first time on the sole of the embryo in the beginning of the fifth fetal month. In about the similar period it was noticeable on the forehead and hypogastrium.With regard to the cause of the bending at the apex of the primordia of the sweat glands, it is necessary that the leading relation with the bending of the apex and the hair bases, and a tendency to bend in the primordia of the sweat gland itself are take into consideration in addition to the newly originated blood vessels and to the rapid development of the epidermis having the relations with the bending.9. The initial region where the glandular lumen in the sweat glandular corpus is formed, is the transitional region from the apical ampulla of the sweat gland to the excretory tubular portion, and this is recognizable on the primordial sweat glands which belong on the forehead of the embryo in the beginning of the fifth fetal month to the hair bases in the stage of the “Bulbuszapfen.”The tubular lumen of the excretory tubule was at first recognized on the forehead of the embryo in the beginning of the eighth fetal month.As for the causes of the formation of the glandular and tubular lumen, pressure by accumulated liquid, necrosis of the axial cells in the ampulla mentioned by many scientists were found.10. No formations of the glomerulus on the glandular corpus were recognizable in the embryo by the end of the eighth fetal month.11. As for the orifice of the sweat glands into the hair follicles, most of the sweat glands opened their orifice into the hair follicles near the epidermis sometimes some of sweat glands opened their orifice onto the transitional region, between th hair follicle and the epidermis.12. No sweat glands opened their orifice onto the epidermis without any relation to the hair follicles. However, from the beginning of the origin some primordia of the sweat glands arose from the transitional region between the hair bases and the epidermis. In regard to the movement of the orifice onto the epidermis, no evidences were recognizable.

A STUDY ON THE DEVELOPMENT OF THE SWEAT GLANDS OF THE CATTLE EMBRYOS

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