A treatise on diseases of the bones / By Thomas M. Markoe.

  • Markoe, Thomas M. (Thomas Masters), 1819-1901.
Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on diseases of the bones / By Thomas M. Markoe. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    wliich it grows by slowly calcifying its oldest and deepest layers until they Iteconie part of the stony structure itself, while its younger and softer parts are sprouting and growing, to repeat, in their turn, the same process of solidification, till reefs, and islands, an<l continents, are ui)reared by their mar- vellous multiplication. Thus, too, in some of the other of the lowest zoophytes, whose whole body is little more than a mass of jelly, and whose almost oidy function is nutrition of the simplest and most direct character, we can only regard its silicious or calcareous covering as bestowed upon it for pro- tection against the rude agencies to which, in the ever-moving waters of the ocean, it is constantly exi)Osed, and without which protection even its incalculable fertility might not be able to save its species from extinction. In the higher classes of the Radiata, when distinct digestive, respiratory, and gen- erative systems begin to show themselves with some definite powers of locomotion, we find a framework which is designed not merely for protection, but evidently also for preserving form, and for giving eftectiveness to the limited movements which the animal is capable of making. In the Mollusca, where the vegetative or organic is developed so greatly in excess of the animal or locomotive system, we tind the shell serving the pur])ose almost exclusively of protection, neither support nor locomotion depending on it in any very marked degree; while in the Articidatu, which as a class })resent a ]>rei»onderating develojunent of the locomotive system, we find tlieir hard cal- careous or horny casing so arranged as not only to preserve their perfect shape, but to give variety and power to the com- plicated movements by which they arc characterized, ajul upon which tlieir vital functions in a great measure depend. In the Mammalia, s<tme of the more delicate organs, as the brain and lungs, recpiire the ])rotection of a bony envelope like the skull and the thorax ; all parts rccpiire the supj)ort neces- sary to miiintain their shape; and the same support is neces- sary for the action of the muscles on the unyielding levers sup- plied by the boms. The mechanical necessities of the case, then, are threefold: 1. Firnmoss of tissue sufiieient to afitinl the requisite support and protection ; 'J. Mobility of one part ujxin another, such as