24 RESEARCHES ON THE INTIMATE STRUCTURE OF BONE. 



Schreger states that in the bones of a child, the earthy 

 matter constitutes one-half, that, in the bones of an adult it 

 amounts to four-fifths, and in those of an old person to seven- 

 eighths of the whole mass. 



Fourcroy and Vauquelin, found no fluate of lime in their 

 analysis, but met with some iron, manganese, silex, alumine, 

 and phosphate of ammonia. The luminous appearance of 

 bones at night, when the animal matter is undergoing decom- 

 position, is believed to be owing to the phosphorus liberated 

 from combination ; and in such instances, Bichat has found an 

 oily or unctuous exudation at the luminous points. 

 The observations of M. Gerdy* who has carefully investi- 

 gated the structure of the bones, coincide in a great degree 

 with the microscopical researches of the German anatomists 

 shortly to be noticed. He considers that there are four distinct 

 tissues in bone, which have been confounded together up 

 to this time ; the compact, the canaliculated,j* reticular, and 

 areolar or cellular. 



The compact tissue has in certain bones a fibrous appearance ; 

 its fibres appear longitudinal in long bones, radiated or irregu- 

 larly divergent in many of the flat. The whole of this fibrous 

 appearance is illusory, as Scarpa asserted, and is owing to the 

 grooves or canals in the compact portion of the bones which 

 lodge vessels, (canals of Havers,) run longitudinally in the 

 compact portion, and have orifices leading into them from the 

 outer surface ; between the canals is found projecting the pro- 

 per structure of the bone, which is necessarily thin, and from 

 the great number of these vessels, presents the appearance of 

 fibres. The vascular openings leading into the grooves, are 

 some perpendicular, and some oblique in regard to the surface 

 of the bones. They all conduct vessels into the compact tissue. 

 The compact tissue, as will be better seen under the head of 

 formation of bone, is primitively a compound of osseous tubes 

 developed around the vessels. These osseous tubes which are 

 longitudinal in the long bones and radiated in the flat, are so 



* Bulletin de Clinique, 1835-6. 



f The canaliculated tissue is formed by the canals of Havers, which lodge 

 blood-vessels. 



