OP THE BONES. 393 



rise to numerous works and engravings. It still, however, 

 presents, on some points, many obscurities to be cleared up, 

 which, perhaps, depend more than is imagined upon vague 

 comparisons which have been made between the alterations of 

 the bones and those of the soft parts in general, without speci- 

 fying any tissue in particular. It is a point of anatomy and 

 pathology which is highly worthy of attention. 



6 IS. Original vices of conformation* are rare in the long 

 bones; less so in the short bones; frequent in the broad bones; 

 rare in the bones of the limbs; more frequent in those of the 

 trunk, especially in the sternum and ribs; still more so in the 

 bones of the head ; and especially in those of the cranium ; and 

 more so in those of the arch than in those of the base. 



The most common variations are observed in the reunions 

 of the bones, then in their figure, then in the form of their 

 holes, and, lastly, in their apophyses. 



Most of these vices of conformation, like those of all the 

 parts, appear to depend upon a defect of formation. Some of 

 them, however, seem to depend upon an excess of formation. 

 They are of rare occurrence in the bones and in the parts of 

 bones which are first ossified, and, on the contrary, more com- 

 mon in the parts which form last. 



619. The bones are sometimes consecutively altered so as 

 to be increased or diminished in size. Besides the spina ven- 

 tosa and osteosteatoma, already mentioned, and which are 

 merely a dilatation of the bones: the exostoses, whether ex- 

 ternal or internal, which are only the periostosis and the spina 

 ventosa ossified; the bones are also sometimes the seat of a 

 hypertrophy. The bone is then tumefied, and there is an in- 

 terstitial deposition which keeps up or increases their original 

 density. In all cases there is an augmentation of weight. At 



1793. c. F^Clossius, uber die Krankheiten der Knocken. Tubingen, 1798. 

 J. Howship, in Med. Chir. Transac. vol. viii. and x. 



* Van Doeveren, Observ. Osteol. varios naturae, lusts in ossibus. hum. corp. 

 exhibent; in Obs. Acad. Specim. Lugd. Bat. 1765. Sandifort, de ossibus 

 diverso modo a solitd conformatione abhtdentibus, in Observ. Anat. Pathol. , 

 Lib. iii. and iv. Lugd. Bat. 1777-81. Rosenmuller, de ostium varietatibus. 

 Lips. 1804. 



