File:A text-book on physiology - for the use of schools and colleges - being an abridgment of the author's larger work on human physiology (1866) (14581505340).jpg

Identifier: textbookonphysio00drap (find matches)
Title: A text-book on physiology : for the use of schools and colleges : being an abridgment of the author's larger work on human physiology
Year: 1866 (1860s)
Authors: Draper, John William, 1811-1882
Subjects: Human physiology Physiology
Publisher: New York : Harper & Bros.
Contributing Library: Francis A. Countway Library of Medicine
Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School

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. 297 solid and flexible, sometimes clavate in form, and some-times having numerous points. They are about the y^-of an inch in height, and the -^io- of an inch in diameterat their base, these dimensions varying, however, verygreatly with the situation. They contain a loop of blood-vessels and a twig of a sensory nerve, for all the centrip-etal nerves, with the exception of those devoted to thespecial senses, may be regarded as concerned in this func-tion. The papillae contain an elastic substance —axilebody, as it is termed — serving to heighten the sense,and the yielding structure of the skin aids in the sameeffect. The papillae are covered over with the cuticle,through which, therefore, all action on them must takeplace. Fig. 94 represents simple papillae of the palm, the cu-ticle having been detached. Fig. 95, compound papillae,with two, three, or four points: a, base of a papilla; b b b,separate processes; ccc, processes ofpapilke whose basesare not visible. Fig. 95. Fig. 94,
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Simple papillse, magnified 35 di-ameters. Compound papillse, magnified 60 diameters. The mode in which the nerve fibre terminates in thepapilla is as yet doubtful, some asserting that it is ar-ranged as a returning loop, and some that it is by apointed extremity. The sensitiveness of a part is in proportion to thenumber of papillae it contains. Tables have been con-structed setting forth the relations of different regions,as determined by placing a pair of compasses, the pointsof which were covered with cork, on the parts to T^etried, the eyes being shut, and closing the compasses un-til the pieces of cork could no longer be distinguished asseparate. It appears that this will take place on the tipof the tongue when the points are the -^ of an inch apart; How may the sensitiveness of a part be measured ? N 2 298 FEELING AND TOUCHING—TICKLING. on the tip of the third phalanx, at the -^ of an inch; onthe lips, the one sixth of an inch; tip of the great toe,half an inch; the lower part

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