20 STRUCTURE OF THE BONES. 



a long period in a Papin's digester, the other element of the 

 bone may be obtained its earthy structure in a separate 

 state, representing the original perfectly, in size and shape. It 

 is then perfectly white, and is so light and brittle as to crumble 

 on the slightest touch. 



Exposure of bones for a long time to the action of the climate, 

 will cause it to shell off in layers and fall into powder, from the 

 same cause, the destruction of its animal matter. 

 A bone macerated in acid, or well incinerated, may be torn 

 or split in particular directions, more readily than others, and 

 manifests an apparent fibrous arrangement. 



*"" In regard to the disposition and arrangement of these fibres, 

 anatomists differ, though it has been with them a subject of 

 much research. The length of each fibre is limited, running 

 but a small part of the length of the long bones, but is much 

 greater than its breadth and thickness. The greater part arc- 

 longitudinal, that is, run in the direction of the axis of the 

 bone ; some are transverse and some oblique. From the 

 shortness and varied direction of the fibres, and the cellular 

 appearance of the bone when macerated, Scarpa denied 

 entirely, the existence of a fibrous arrangement in the bones, 

 and considers them composed throughout, exclusively of 

 cellular substance, more or less compacted. 

 Malpighi and Havers, believed the bones made up wholly of 

 concentric lamellae, -formed of fibres and filaments, encrusted 

 with osseous matter, laying over each other like the leaves of 

 a book. Gagliardi believed also, that these lamellae were united 

 together by little pins of the same material : some of which 

 were straight, some oblique, and some he fancied had round 

 heads. De Lasone says that these lamellae are made up of ossi- 

 fied fibres, united by oblique ones, and Reich el, that the lamellae 

 and fibres, form a porous tubulated tissue, continuous with 

 the spongy substance.* According to J. F. Meckel, the proper 



* The opinions of these different anatomists are interesting mainly as con- 

 nected with the history of the science. The discrepancies existing between them, 

 may now readily be reconciled, since the true composition or structure of bone 

 has been rendered apparent by the use of the microscope. See page 46. p. 



