. Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus. Vertebrates -- Embryology; Comparative embryology. Fig. 19. Sections of experimental, cryptorchid, guinea-pig, seminiferous tubules and interstitial tissue. (Modified from C. R. Moore in Sex & Internal Secretions, Williams & Wilkins, Baltimore, 1939.) (A) Testis confined to abdomen for three months. (B) Testis confined to abdomen for six months. Observe degenerate state of seminiferous tubule after six months' confinement. Interstitial tissue not greatly affected by confinement. changes wi
. Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus. Vertebrates -- Embryology; Comparative embryology. Fig. 19. Sections of experimental, cryptorchid, guinea-pig, seminiferous tubules and interstitial tissue. (Modified from C. R. Moore in Sex & Internal Secretions, Williams & Wilkins, Baltimore, 1939.) (A) Testis confined to abdomen for three months. (B) Testis confined to abdomen for six months. Observe degenerate state of seminiferous tubule after six months' confinement. Interstitial tissue not greatly affected by confinement. changes with temporary sterility (fig. 21). Recovery, however, is the rule in the latter instance. Summarizing the effects of such experiments involving temperature, Moore (in Allen, Danforth, and Doisy, '39, p. 371) concludes: "The injury developing from applied heat, although more rapidly effective, is entirely similar to that induced by the normal body temperature when the testicle is removed from the scrotum to the ; The position of the scrotum and its anatomical structure is such as to enhance its purpose as a regulator of testicular temperature (figs. 2, 6). When the surrounding temperature is cold, the contraction of the dartos muscle tissue of the scrotal skin contracts the scrotum as a whole, while the con- traction of the cremaster muscle loops pulls the testes and the scrotum closer to the body, thus conserving the contained heat. When the surrounding tem- perature is warm, these muscles relax, producing a more pendulous condition to permit heat loss from the scrotal Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Nelsen, Olin E. (Olin Everett), b. 1898. New York, Blakiston
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