Observations on certain parts of the animal oeconomy. Inclusive of several papers from the Philosophical transactions, etc / by John Hunter ... With notes by Richard Owen.
- John Hunter
- Date:
- 1840
Licence: Public Domain Mark
Credit: Observations on certain parts of the animal oeconomy. Inclusive of several papers from the Philosophical transactions, etc / by John Hunter ... With notes by Richard Owen. Source: Wellcome Collection.
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![had a connexion with these powers, would still have the stimulus of perfection given to them. Re The different appearance of the bulb and the muscles would seem to point out, in the perfect male, the enlargement of the bulb to be for the purpose of a receptacle for the semen; for although { have denied the vesicule to be reservoirs, yet, as it was necessary that the semen should be accumulated somewhere before ejection, I shall endeavour to prove, from the mode of copulation in the animals we are best acquainted with, that the bulb is intended for that purpose. Let us, therefore, give a short account of the different parts con- . cerned in coition ; and by observing the dependence which they have upen one another, see how this proof will come out. The erection of the penis is produced by a stop being put to the returning blood, and this stoppage is so complete, that no mechani- cal pressure applied to the body of the penis can force the blood on into the veins. ‘This erection answers two purposes; it gives size and strength to the penis, and it renders the canal of the urethra smaller. The corpus spongiosum of the urethra and the glans, which ‘is only a continuation of it, are filled with blood from the same cause, but not so completely as the body of the penis, since from them it can be forced out into the veins by pressure.* This accu- mulation of blood in the corpus spongiosum diminishes the canal of the urethra so much, that any pressure upon one part of it will have a considerable effect upon the other; not only by lessening its capa- city at the part pressed, but by forcing the blood forward, the parts beyond will be still more distended, and: consequently the canal of * In April 1760, in the presence of Mr. Blount, I laid bave the penis of a dog, almost through its whole length; traced the two veins that came from the glans (which in this animal makes the largest part of the penis), and separated them from the arteries by dissection, that I might be able to compress them at pleasure without affecting the arteries. I then compressed the two veins, and found that the glans and large bulb became full and extended; but when I irritated the veins, in order to see if there was any power of contraction in them which might occasionally stop the return of the blood, no such appearance could be observed. — _ 4([From this experiment, it is obvious that Hunter regarded the stoppage of the circulation through the veins as being produced by external compression. Douglas (Myographiz Comparate Specimen, p. 9), had previously described the muscles which compress the vena dorsalis penis in the dog; and Cowper had more fully and particularly detailed the structure and actions of the muscles which have a corresponding office in the opossum, observing that ‘the muscles of the cavernous bodies of the penis of this creature, having no connexion with the os pubis, cannot apply the dorsum penis to the last-named bone, and compress the vein of the penis, whereby to retard the refluent blood and cause an erection, _ as we have observed in other creatures; but some large veins of the penis here take a different course, and pass through the middle parts of the bulb, and are only liable to compression made by the intumescence of the museles C C (mus- cles of the bulb) that inclose them. « But the chief agent in continuing the erection of the penis in this animal is the sphincter muscle of its anns, or rather cloaca; and not only the sphincter muscle of the cloaca of the male opossum, but that of the female also closely embraces the penis in coition, and effectually ‘retard the refluent blood from its corpora cavernosa, by compressing the veins of the penis.” (Phil. Trans., vol. xxiv. 1704, p. 1584.) ] PE ae SS ean Ee,](https://iiif.wellcomecollection.org/image/b33292292_0077.jp2/full/800%2C/0/default.jpg)
