. Quain's elements of anatomy . become removed byabsorption, and take no part, directlyor indu-ectly, in the production of thesecondary bone. The latter view of thematter was taken by Loven, and it wasalso regarded by Sharpey as in all pro-bability the more correct. It is difiicult to decide between theseviews. All that can be said is that the line of demarcation between the cartilage-cells and the osteoblastic tissue isexceedingly abrupt (fig. 108), and that the latter often, if not always, terminateseither by a dilated vascular loop, or it may be by a developing capHlary filledwith blood coi
. Quain's elements of anatomy . become removed byabsorption, and take no part, directlyor indu-ectly, in the production of thesecondary bone. The latter view of thematter was taken by Loven, and it wasalso regarded by Sharpey as in all pro-bability the more correct. It is difiicult to decide between theseviews. All that can be said is that the line of demarcation between the cartilage-cells and the osteoblastic tissue isexceedingly abrupt (fig. 108), and that the latter often, if not always, terminateseither by a dilated vascular loop, or it may be by a developing capHlary filledwith blood coi-puscles. Except that they are generally much shrunken andirregular in form (at least after death or the action of reagents), the cartilage-cells show no absorption and no distinct evidence of division, and it may beremarked that this is also the case wheU; as sometimes happens, they have notdisappeared before the advancing subperiosteal tissue, but remaui for a time stilloccupying an untouched primary areola (see fig. 105, c).. 112 BONE OR OSSEOUS TISSUE. As ossification advances towards the ends of the bone, the portion asyet cartilaginous continues to grow at the same time, increasing inevery dimension. Tlie part already osseous increases also in circum-ference ; fresh boue being continually deposited in the subperiostealmembranous tissue outside that which is first formed on the surface ofthe cartilage (figs. 105, 109). The subperiosteal deposit takes place inthe same way as in the formation of a membrane bone. Bony spiculesprolonged by bunches of osteogenic fibres (fig. 109, o) project out fromthe previously formed layer, into the intervals between the the union of the spicules these become in like manner enclosed inchannels whose walls are gradually thickened by deposits of osseouslamella, between which some of the osteoblasts are left behind as bone-corpuscles in lacunge, whilst others remain surrounding the blood-vesselsin the vascular channels. Fig. 10
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