File:Evolution and disease (1890) (14761706444).jpg

Identifier: evolutiondisease00blan (find matches)
Title: Evolution and disease
Year: 1890 (1890s)
Authors: Bland-Sutton, John, Sir, 1855-1936
Subjects: Diseases Medical genetics Abnormalities, Human Animals Disease Congenital Abnormalities
Publisher: New York : Scribner & Welford
Contributing Library: Francis A. Countway Library of Medicine
Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School

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canines of a Boar mouth, seems to have crossed the buccal cavity so that itsapex rests on the inner side of the right lower jaw.This is by no means an unique specimen, for on inquiryI have come across numerous examples of this aberrantgrowth of the lower canines of boars. The excellentmuseum of the Veterinary School at Alfort has a speci-men resembling that of Cheselden. I have a canine ofthis character from a boar which measures thirty centi- 2o4 E VOL UTION AND DISEASE. metres round the curve. In the museum of the Odonto-logical Society of Great Britain the incisor of a hippo-potamus (a huge pig) is preserved which has described acomplete circle, the point of the tooth re-entering itsown pulp chamber. The circle formed by this overgrowntooth has a diameter of forty centimetres. The remarkable tusks of the babirussa, especiallywhen the animal is confined in zoological gardens, areexceedingly prone to take an abnormal course, andinstead of forming graceful curves beside the head, may
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Fig. iio.—The head of a Babirussa. The upper canines are re-entering the skull. deviate towards the middle line and enter the skull.Such an example taken from life is sketched in fig. 110 ;in order to prevent disaster the babirussa was thrown andten centimetres of the tusks removed ; they had, how-ever, penetrated to the depth of twelve millimetres. This deviation of the upper canines may be in partaccounted for by the fact that, like tusks in general,they are slightly movable in their sockets, hence byrubbing them against the sides of the dens or cages,a false direction is impressed upon them. Careful ANATOMICAL PECULIARITIES OF TEETH, 205 consideration of such cases has induced me to believethat these aberrant tusks may be regarded as arisingin the first instance as overgrowths, and that suchmalformations being frequently repeated the tendencyhas been transmitted to the offspring and eventuallyperpetuated as a normal character of the male. The various steps of such a process may b

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