. Quain's elements of anatomy . f compact substance. In the complex or mixed bones, suchas the vertebras, the two substances have the same general relation toeach other ; but the relative amount of each in different parts, as wellas their special arrangement in particular instances, is very various. On close inspection the cancellated texture of bone is seen to be formedof slender bars or spicula and thin lamellEe, which meet together andjoin in a reticular manner, producing an open structure which hasbeen compared to lattice-work (cancelU), and hence the name usually MINUTE STRUCTUEE OF BONE.
. Quain's elements of anatomy . f compact substance. In the complex or mixed bones, suchas the vertebras, the two substances have the same general relation toeach other ; but the relative amount of each in different parts, as wellas their special arrangement in particular instances, is very various. On close inspection the cancellated texture of bone is seen to be formedof slender bars or spicula and thin lamellEe, which meet together andjoin in a reticular manner, producing an open structure which hasbeen compared to lattice-work (cancelU), and hence the name usually MINUTE STRUCTUEE OF BONE. 89 applied to it. In this way considerable strength is attained Avithoutundue weight, and it may usually be observed that the strongest laminaerun through the structure in those du-ections in which the bone hasnaturally to sustain the greatest pressure. The open spaces or areolaof the bony network communicate freely together; in the fresh statethey contain marrow or blood-vessels, and give support to these softparts. Piff. Fig. 89.—A, Transvekse section of a bone (ulna) deprived of its bakth by ACID (Sharpey). The openings of tlie Haversian canals are seen. Katiii-al size. A small jportion isshaded to indicate the part magnified in Fig. B. B, Part of the Section A, magnified 20 diameters. The lines indicating the concentric lamellte are seen, and among them the lacuuajapi^ear as little dark specks. Haversian canals.—The compact tissue is also full of holes ; these,which are very small, are best seen by breaking across the shaft of along bone near its middle and examining it with a common magnifyingglass. Numerous little round apertures (fig. 89 A) may then be seenon the broken surface, which are the openings of short longitudinalpassages running in the compact substance, and named the Ilttversicmcanals, after Clopton Havers, an English physician and writer of theseventeenth century, who more especially called attention to run in these canals, and th
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