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.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![and they are fastened by the same kind of ligament to the inside of the parietes of the abdomen at the groin. Now in that animal I find that the lowermost fibres of the internal oblique muscle, which constitute the cremaster, are turned inwards at the place where the spermatic vessels come out in other animals, making a smooth edge or lip by their inversion, and that then they mount up on the liga- ment to the lower end of the testis.14 Sometimes in the human body, and in many other animals, and very often in sheep, the testes do not descend from the cavity of the abdomen till late in life, or never at all. In the ram, when the testis is come down into the scrotum, the cremaster is a very strong muscle; and, though it be placed more inwards at its beginning, it passes down pretty much as it does in the human body, and is lost on the outside of the tunica vaginalis; but in the ram, whose testis still remains suspended in the abdominal cavity, I find that the cremaster still exists, though it is a weaker muscle; and instead of passing downwards, as in the former case, it turns inwards and upwards, and is lost in the peri- toneum that covers the ligament which attaches the testis to the parietes of the abdomen, which in this state of the animal is about an inch and a half in length. In the human foetus, while the testis is retained in the cavity of the abdomen, the cremaster is so slender that I cannot trace it to my own satisfaction, either turning up towards the testis or turning down towards the scrotum. Yet, from analogy, we may conclude that it passes up to the testicle; since in the adult we find it inserted or lost on the lower part of the tunica vaginalis, in the same manner as in the adult quadruped.! The peritoneum, which covers the testis and its ligament or gubernaculum, is firmly united to the surfaces of these two bodies; but all around, to wit, on the kidney, the psoas, the iliacus, internus, and the lower part of the abdominal muscles, that membrane ♦ [The apparent anomaly of this, as of almost every other natural structure, disappears when we attain the requisite amount of knowledge respecting the conditions under which it exists. The testes of the hedgehog, like those of the mole, (see p. 66,) are subject to remarkable periodical enlargement at the season of copulation, when they are drawn down by the cremaster to the external ring. In this situation they are favourably placed to be affected by the expulsive actions of the diaphragm and abdominal muscles, by which they are eventually protruded and the cremasteric pouch is inverted. As the testes diminish in size their muscular covering contracts upon them and returns them into the abdomen.] | [By such a pre-arrangement of the relations of the cremaster to the testis the necessity for the latter to overcome in its passage outwards the resistance of the inferior fibres of the transversalis abdominis and obliquus internus is obviated. It cannot reasonably be doubted that the cremaster exists, as such, in the human fcetus prior to the descent of the testis, since it is indubitably present and attached to an abdominal testis in animals where no mechanical cause could have operated to produce this disposition of the muscular fibres. Besides, the use of the cremaster as a supporter and compressor of the testis is obviously too important for such a connexion to have been allowed to result from the gland accidentally, as it were, pushing before it some opposing fibres of the abdominal muscles in its progress outwards, as Carus imagines. See his Comparative Anatomy, by Gore, vol. ii., p. 347.]](https://iiif.wellcomecollection.org/image/b21131545_0013.jp2/full/800%2C/0/default.jpg)
