File:Evolution and disease (1890) (14764065265).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

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
elephant, and narwhal, the tusks protrudebetween the lips ; in the babirussa the lower tusks pro-trude in this manner, but the upper pair make their waydirectly through the skin covering the upper jaw.Tusks, like the teeth of rodents, grow from persistentpulps, and many interesting pathological conditions arisein consequence of this peculiarity. Among boars there is a tendency for the tusks to growabnormally and describe circles. An example of thiswas described in 1733 by Cheselden ;x the specimen is1 Osteographia, London, 1733. ANATOMICAL PECULIARITIES OE TEETH. 203 preserved in the museum of the Royal College of Sur-geons, England, and is figured below. In this specimen(fig. 109) the lower canines have grown excessively,turned backwards, and re-entered the mouth by piercingthe integument and the jaw. The right tusk has tun-nelled the bone for a distance of three inches and re-appeared on the floor of the mouth and has described acomplete circle. The left tusk, after re-entering the
Text Appearing After Image:
Fig. 109.—Abnormal growth of the lower 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 form

Note About Images