File:Evolution and disease (1890) (14783894963).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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Fig. 71.—A Lamb with coalesced supernumerary pelvic limbs,(After Gurlt.) pelvis. In this case the nether opening of the alimentarycanal is double also. A much more obvious case than this is representedin the chick (fig. 72). For some reason or othersupernumerary legs are very common in fowls, ducks,geese, pheasants, and lambs. In many cases posterior dichotomy of the axis maybe indicated by one limb only, the other undergoingsuppression., 128 E VOL UTION AND DISEASE, Dr. Tuckerman * has placed on record an account ofsuch a specimen. The subject was a frog (Ranapalustris) ; it was blown from out a crevice in a ledgeof mica schist during some blasting operations. Thecrevice was twelve feet below the surface and measuredonly a few lines at its widest point ; flowing into the
Text Appearing After Image:
Fig. 72.—A Chick with supernumerary legs. crevice was a small stream of running water, whichundoubtedly conveyed either the eggs, or the frogs inthe larval stage, to the interior of the rock, as thebreach in the ledge was much too small even to admitthe passage of a very young frog. This frog had, as 1 Journal of Anatomy and Physiology, vol. xx. p. 516. DICHOTOMY. 129 represented in fig. 73, a third hind limb projectingposteriorly between the normal legs. On dissection itwas found attached by muscle and tendon to thesymphysis pubis : it presented the usual segments offemur, crus, and pes, and was furnished with twowell - formed digits and the rudiment of a third.During life it was found that when the skin of thelimb was stimulated the frog would jump quicklyaway ; sometimes oft-repeated stimulation would callforth a muscular contractionin the limb. Occasionallymovements were observedin the abnormal limb whenthe frog was left entirely toitself. It has already been men-tioned that in

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