ANATOMY. 



213 



form substance without fibres, plates, or cells 

 penetrated every where by delicate blood vessels 

 Those vessels admit of being injected with size, or 

 turpentine and vermillion, pretty freely ; but from 

 the opacity and hardness of the texture in its na- 

 tural state, it is impossible to trace them with the 

 eye, or by dissection, into its more interior parts 

 There is a very simple method, however, by which 

 a piece of bone, after it has been minutely injected, 

 may be rendered aknost perfectly transparent, 

 and then its blood vessels are displayed in the 

 most beautiful manner. The method consists in 

 steeping the piece of bone in dilute muriatic acic 

 for a few hours, or days, or weeks, according to 

 the thickness of the specimen, until it has be- 

 come quite soft and pliable. It is then to be well 

 washed, and after it has been gradually, but incom- 

 pletely dried, it is to be plunged into spirit of turpen- 

 tine. The instant it is immersed in this fluid, it be- 

 comes transparent, but the substance injected into 

 the arteries retaining its colour and opacity, the most 

 minute ramifications of these vessels are distinctly 

 seen. There can be no doubt, that bone is also pos- 

 sessed of absorbents and nerves, but these have not 

 yet been traced in it. 



Any individual of ordinary intelligence and ad- 

 dress, may, by the above and other more simple 

 processes, satisfy themselves on many important 

 facts in osteology, if, for example, we wish to 

 demonstrate the substance of bone, which has 

 been divided into three heads: compact, as in the 

 bodies of the long bones, spongy, as in the ex. 

 tremity of the long bones, and retictilar, called 1 

 also the cancelli, as in the cavity of bones, which 

 have marrow or medullary substance, we may pro- 

 ceed as follows: 



Let a thigh bone be well boiled or macerated, 

 and then let a perpendicular section be made, in 

 other words, let the bone be sawn in two, and the 

 three substances of bones will be very strikingly 

 exhibited ; the compact will be seen forming its 

 external part, the spongy at the extremities, crowd- 

 ed with small cells, or as they are called by ana- 

 tomists, cancelli, and the reticulated in its cavity, 

 which forms a reservoir for the marrow. The 

 compact substance is composed of many laminae, 

 or plates, composing a firm, hard substance, and 

 these laminae are easily distinguished in bones that 

 have been partly exposed to calcination, or boiled 

 for any length of time in a strong alkaline ley, or 

 steeped in dilute muriatic acid. In man, and in 

 other animals, these laminae mostly separate on 

 exposure to air, and hence the laminated portions, 

 which frequently peel off, are called exfoliation in 

 surgery. The fibres of the spongy and reticulated 

 substance are extremely varied in their direction, 

 and some variety occurs in this respect in the com- 

 pact substance. Thus, in flat bones, as those of 

 the head, they are disposed in the form of rays, 

 and are seen converging from the circumference to 

 the centre, while in the cylindrical bones they 

 seem to be placed in parallel directions. The di- 

 rection of the bony fibres, and all the above cir- 

 cumstances, are most satisfactorily demonstrated : 

 1. In the parietal bones of a foetus which have 

 been macerated, and cleared of the soft parts, as 

 they exhibit very beautifully the radiated direction 

 of the bony fibres : 2. By macerating a portion of 

 the adult femur or thigh-bone from the body of the 

 bone in dilute and muriatic acid, then separating 

 with forceps or pincers, the laminae: this simple 

 manipulation will distinctly exhibit the laminae of 



the bones ; and, 3. The os femoris, or thigh bone of 

 a slink calf, or a pig, if macerated, or boiled, and 

 either kept in spirit, or dried, and then put in 

 spirit of turpentine, will show the parallel direc- 

 tion of the bony fibres. 



It is a remarkable fact, that the sulphuric, nitric, 

 muriatic, and acetic acids, when properly diluted, 

 all soften bone, and render it pliable, without its 

 being possible to discover, by the most minute in- 

 spection, that a single particle of its substance has 

 been removed. We have repeated this experiment 

 many times, and on some of the most delicate por- 

 tions of osseous substance in the body. The form 

 and size of the slenderest fibre remains unaltered 

 by the process, but our experience has convinced 

 us that the muriatic acid is best adapted for the 

 purpose. In proportion as the piece of bone be- 

 comes soft by this operation, it loses its yellow 

 colour, and becomes bluish, or gray, approaching 

 somewhat in appearance to cartilage. The very 

 opposite effects are produced on osseous substances 

 by heat. If a bit of bone be burned in a charcoal 

 fire, of which the heat has been gradually raised to 

 whiteness, and it be then carefully removed, and 

 cooled very slowly, it will be found to have become 

 exceedingly brittle, and of a pure white colour. 

 Still not a particle of the substance will appear to 

 have been destroyed. If the process have been 

 carefully conducted, the bone will have precisely 

 the same shape and dimensions as before. 



Having thus shortly sketched the general struc- 

 ture and texture of bones, we shall briefly describe 

 some of the other most prominent peculiarities of 

 the osseous system. Bones, in respect to form or 

 figure, have been divided into broad or flat, long 

 and round, and cylindrical, and long, and irregular 

 shaped bones ; have been subdivided into a body, 

 and extremities, and flat bones into body and mar- 

 gins. The long bones in general, belong to 1 the 

 parts of locomotion, where they become levers, 

 moved in various directions by the muscles. The 

 broad or flat bones are little connected with loco- 

 motion, serving chiefly for the insertion of muscles, 

 which proceed to the long bones ; the broad bones 

 also form cavities, such as those of the skull and 

 pelvis. There is another class of bones which, by 

 some anatomists, have been denominated the short 

 bones : these are situated in those parts in which 

 solidity and motion must be united, as in the spine, 

 the wrist, and the instep, where their number in- 

 sures these two properties, namely, solidity and mo- 

 tion, because the force of external mechanical shocks 

 expended on the wide surface by which they are 

 connected, and because by their individual partial 

 motions there results collectively a very extensive 

 jeneral one. 



Bones, too, have been variously named, some 

 from their situation, as the frontal, parietal, occi- 

 pital, nasal, molar, &c., others from their figure, as 

 the ethmoid bone, clavicle, naviculare, tibia, &c., 

 and some from their use, as the sphenoid bone, the 

 maxillary bone, the femur, &c. The processes and 

 avities are named from their figure, as the aceta- 

 mlum, or cup-shaped cavity in the hip-bone, into 

 which the head of the thigh bone is lodged, because 

 ;his cavity bears a resemblance to the vinegar cup 

 of the ancients ; and from similar circumstances of 

 resemblance to different objects, have many of the 

 other processes and cavities of the body received 

 ;heir names ; others again from their use, as the 

 trochanters of the thigh bone, that large and smaller 

 process at the bend of the head of the bone which 



