59 



XL — Additional Observations on the Intimate Structure of Bone. 

 By John Quekett, Assistant Conservator of the Museum of the 

 Royal College of Surgeons of England. 



(Bead November 11, 1846). 



In a paper which I laid before this Society at the meeting held 

 March 18th, 1846, entitled, " On the Intimate Structure of Bone, as 

 composing the Skeleton in the four great Classes of Animals, viz., 

 Mammals, Birds, Reptiles, and Fishes, with some Remarks on the 

 great Value of the Knowledge of such Structure in determining the 

 Affinities of Minute Fragments of Organic Remains," after describing 

 briefly the various parts of which the shaft of a long bone of the 

 Mammalia is composed, viz., 1st, a central or medullary cavity, — 

 2ndly, a series of small canals (Haversian), around which are arranged 

 concentric laminae of bony matter, — 3rdly, of a concentric arrange- 

 ment of spider-like looking bodies, which have been variously termed 

 osseous corpuscles, calcigerous cells, lacunae or bone-cells, each cell 

 having little tubes or canals, termed canaliculi, proceeding from 

 them, — I went on to show that the average length of the bone-cells in 

 the human subject was about ^y^th of an inch, that they were of an 

 oval form, somewhat flattened on their opposite surfaces, and usually 

 one-third greater in thickness than in breadth; that the bones pi 

 birds were all more or less hollow, and the Haversian canals much 

 smaller and more numerous than in Mammalia, that the bone-cells 

 also were of much smaller size, and their long diameters often placed 

 at right angles with the shaft of the bone ; that in the Reptilia the 

 Haversian canals are large and not numerous, but the bone-cells and 

 their canaliculi are remarkable for their very large size, whilst in 

 fishes the Haversian canals were entirely absent in some bones, and 

 abundant in others : when entirely absent, their place appeared to be 

 supplied by bone-cells which presented several peculiarities, serving 

 to distinguish them from those of the mammal, the bird, or the reptile, 

 they being, for the most part, of a quadrate figure, and the canaliculi 

 given off from them but few in number, and readily seen to anastomose 

 freely with the canaliculi from other cells. I then proposed to apply 

 the characters derived from the bone-cells to the determination of the 

 class of animals to which any minute fragment of fossil or other bone 



