On deformity of the lower jaw in the cachalot (Physeter macrocephalus, Linn.) / by James Murie.

  • Murie, James.
Date:
[1865]
Catalogue details

Licence: Public Domain Mark

Credit: On deformity of the lower jaw in the cachalot (Physeter macrocephalus, Linn.) / by James Murie. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    39G DR. J, MURIK ON THE CACHALOT. [Apr. 11, sure, has evidently been atrophied to such an extent that little more than a mere shell of bone is left at the bend. Inflammation of the periosteum {peiiostitis) has likewise occ^f^ed, as may be inferred from the appearance and consistence of the spongy bone thrown out on the surface. The gums, sockets of the t^eth, and the large nerves sent to the long jaw have also been more or less severely implicated; and the manner in which the occlusion of iM& alveoli has taken place, together with, at one place, the apparent gradual diminution of the vascular supply by the regular channels from pressure upon the vessels, all point out that no sudden bend has been the means of producing the deformity, or that it has been an original foetal malformation. On the whole, then, I would be inclined to account for the distor- tion of these jaws by supposing that when the creature was yet very young, its bones more or less soft or cartilaginous, a state of chronic inflammation had been set up in the bones and periosteum just at the bend, either inherently in the substance or from the effects of a concussion. The inflammatory process, continuing for a lengthened period, would give rise to enlargement and induration of the osseous tissue at the point mentioned, and according to the amount of local irritation and fresh deposition of osseous tissue would the abnormal curve of the bone be produced. The manner in which inflammation of the hoof in Ruminants occasionally causes it to curl upwards may be taken as a familar example; only in the case of the jaws of the Cachalot the increase of growth and swerving of the bone from its usual direction would be effected by the hypertrophy of the one side pressing against and being reflected from its fellow, which it at the same time would drag along with it, while the increase and corre- sponding diminution of substance at the different points would pro- duce the twist upon itself which each ramus possesses. P.S. Since the above was written, Mr. Flower has informed me that he has seen a lower jaw of a small Cachalot distorted in a manner similar to those above described, though less curved. The specimen is in the Museum of the Literary and Philosophical Society of Hull. Along with the two instances recorded by Mr. Beale, this would make a total of six authenticated cases of deformity, and four, at least, of these occur in animals not full grown, but whe- ther males or females is uncertain, excepting the British Museum specimen, which may be considered a female. For I find, according to Professor Owen (Odontography, pp. 353, 354), that in this spe- cies of Cetacean the difference of sex is easily distinguishable by the lower jaws alone, the male having twenty-seven, while the female has only twenty-three, teeth in each ramus, and the size of the jaws in the latter is also a third shorter. The fact of one specimen, therefore, being a female would invalidate Mr. Beale's corroboration of this deformity only taking place in the fighting males. [8]