280 OF THE PRIMARY TISSUES OF THE HUMAN BODY. 



268. It thus appears that there is no true interstitial growth in Bone ; that 

 is, the parts, through which the ossific process has made its way, are incapable 

 of any further extension than by addition to their surface. By the admirable 

 system of prolongations, however, by which the vascular membrane is conveyed 

 into its intimate substance, we find this method of superficial deposit adapted to 

 the consolidation of parts which are at first sketched out (as it were) by a slight 

 osseous reticulation ; whilst by the facility with which the bony matter is absorbed 

 in the internal part of the shaft, at the same time that it is being deposited on 

 its exterior, the same effect is produced, as if the whole cylinder could enlarge 

 uniformly by a proper interstitial growth, in the manner of the softer tissues. 

 Much of our information regarding the mode in which new*osseous matter is de- 

 posited, is derived from observations made upon the bones of animals that have 

 been fed with madder; for this coloring matter, having a strong affinity for bone- 

 earth, tinges all those parts which are in close relation with the vascular surfaces. 

 In very young animals, a single day serves to color the entire substance of the 

 bones ; for there is in them no osseous matter far removed from a vascular sur- 

 face. At a later period, however, the coloring matter is deposited less rapidly ; 

 and is found to be confined to the innermost of the concentric laminae of bone 

 surrounding each Haversian canal, showing that this is the last formed. When 

 madder is given to a growing animal, the external portion of the shaft is first 

 reddened ; showing that the new formation takes place exclusively in that situa- 

 tion. And if, when time has been allowed for this part to become tinged, the 

 administration of the madder be discontinued, and the animal be killed some 

 weeks afterwards, the red stratum is surrounded by a colorless one of subsequent 

 formation; whilst the colorless layer internal to the red one, and formed previ- 

 ously to it, is thinned by absorption from within. By alternately administering 

 and withholding the madder, a succession of colored and colorless cylinders may 

 thus be formed in the shaft of a long bone ; which present themselves as concen- 

 tric rings in its transverse section. 



269. The nature of the Ossifying process receives some additional light from 

 the abnormal forms, in which it occasionally presents itself in Cartilages that 

 are usually permanent ; as well as in various Fibrous tissues, such as the coats 

 of the arteries, fibrous and serous membranes, muscular substance, &c. ; and 

 also in the development of Tumors. In most of these cases, the ossific deposit 

 may often be seen to take place, in the first instance, in the form of distinct 

 granules, which gradually coalesce ; or in the form of spicular fibres, to which 

 additions are progressively made, until a solid mass is produced. This adven- 

 titious bone, however, almost invariably differs from true or normal bone, in 

 the want of a regular Haversian system with concentric laminae, and in the 

 absence or imperfect production of the characteristic lacunae and canaliculi. 

 Irregular cavities, however, are scattered through them, which may in some de- 

 gree answer the same purpose ; and these, in osseous tumors which had origi- 

 nally a Cartilaginous basis, may often be plainly seen to be the persistent carti- 

 lage cells, or the nuclei of cartilage cells, the intervening substance having 

 undergone calcification and gradually inclosed them. It is curious that in certain 

 abnormal Cartilaginous growths, the nuclei have a stellate form, and the cartilage 

 cells become fused with the surrounding basis-substance ; so that, when the latter 

 is calcified, the inclosed stellate nuclei present a strong resemblance to the normal 

 lacunae and canaliculi of bone. 1 But it may be stated as a well-established fact, 

 that calcified tissues, having a more or less close resemblance to true Bone, may be 

 produced in a great variety of modes ; and no inference can be fairly drawn from 

 such observations, therefore, in regard to the normal process of Osteogenesis. For 



1 See Mr. Paget's "Lectures on Tumors," in "Medical Gazette," Aug. 8, 1851. 



