Elements of physiology, for the use of students, and with particular reference to the wants of practitioners / by Rudolph Wagner ; translated from the German, with additions, by Robert Willis.

  • Willis Robert, 1799-1878.
Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: Elements of physiology, for the use of students, and with particular reference to the wants of practitioners / by Rudolph Wagner ; translated from the German, with additions, by Robert Willis. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    51/748 (page 23)
    i urine hours afterwards*4. Very low or very high temperatures ! have a like influence in arresting the motions of the spermatozoa; . although those of frogs and fishes still continue active when the • surrounding medium reaches, or even sinks below the freezing ! point. The kind of death which an animal suffers has no influence on the duration of the motions of its spermatozoa*0. § 10. Production of the Spermatozoa. The genesis, or production and development of spermatozoa are subjects of much interest, and very remarkable; both take place : through the entire series of animals after a very similar type, which presents but slight modifications. For the study of this subject, a bird, and that one of the order of Passeres, should be chosen; the circumstance of the pairing time in these creatures being so deter- minately attached to a certain season, affords us an opportunity of watching the genesis and evolution of their spermatozoa in the most clear and satisfactory manner. The testes themselves, accord- ing to their condition, always prefigure the state of evolution of the spermatozoa. In winter the testes present themselves as a couple of small bodies, the size of a pin’s head, or a millet-seed; the seminal vessels are then exceeedingly contracted, but still demon- strable as tortuous canals, lined with an epithelium. Whether the very minute granular bodies, from the —.roth to the vovfth of a line in diameter, which are then contained in their interior, be of a pecu- liar nature, or belong to the epithelium, is doubtful. With the advance of spring, the testes gradually increase in size, and at length are found of twenty, and even thirty times the size and weight they possessed in the depth of winterz7. The seminal -5 Refer back to the observations on the preceding paragraph (§ 8) Annot. 20, 21, 22. 26 h seemed to be perfectly indifferent in what manner the animals were killed whose seminal animalcules I wished to examine; dogs, rabbits, birds, &c. poisoned with strychnine, coniine, &c., the irritability of whose muscular nerves was entirely gone, still afforded me spermatozoa possessed of all their activity, which lasted as long, too, as under any other circumstances. ' The testicles become of extraordinary magnitude, both absolutely and in re ation to the rest of the body, in the duck, and in the common fowl; in the passeres, or singing birds, I also find them very remarkably developed, and the e t testis generally more so than the right. On this subject see my Elements of omparatiye Anatomy (helirb. der vergleichenden Anatomie, S. 248), and my ,ut‘ons t° the Anatomy of Birds (Beitrage zur Anatomie der Vogel), in the 1 lan ^ur'f/en derBaierischen Akademie, lid. II. S. 284. The progressive enlarge- ment of the testis in birds as the pairing time approached, was studied by Mr.