First principles of medicine / By Archibald Billing.

Archibald Billing

Date:: 1831

Credit: First principles of medicine / By Archibald Billing. Source: Wellcome Collection.

14/142 page 6

$is deposited from the blood by precipitation, and we know that the shape depends on the periosteum, or membranous mould in which it is cast; but here we stop, we cannot discover how in the minute embryo in the womb, the membranes were first determined in their shapes; we here arrive at the confines of our know- ledge, and must confess an infinitely wise FIRST CAUSE who does not permit us to know more than the pheno- mena by which we can judge how, in many instances, to avail ourselves of the means to regulate the compli- cated apparatus which HE has endowed with life. The deposition of bone is a combination of chemical precipitation and crystallization, modified by vital actions, as for instance when there is periosteal mem- brane we see that it keeps up a vital state of bone whether in the bone of a leg, or a tooth, when there is no membrane attached as in the enamel of the tooth, crystallization with the temporary membrane which forms the mould decides the form of aggregation; in case of fracture of a bone the surrounding parts decide the form of the CALLUS which reunites it. Whilst bone is growing, (as shewn by the common experiment of feeding young animals with madder so as to produce variegated deposits) there is a change as to disposition of the bony matter going on, but there is no reason to suppose that the substance of a healthy sound bone of an adult is changing, no more than a tooth, or the wall of a castle though there are preparations ready to repair a breach if made. The arteries of the periosteum are always ready to repair, and as soon as they get notice they begin to de- posit (the bricks and mortar); What is the notice?$

First principles of medicine / By Archibald Billing.

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