No. III.A.] APPENDIX. 151 



No. III.A. 



ON THE STRUOTUHE OF NORMAL AND ADVENTITIOUS 



BONE. 



To the Editor of the ' Medical Gazette.' 



Sib, — The enclosed paper contains the results of observations on the 

 structure of bone, made at various times during the last three years. It 

 was read before the Royal Society last -winter, and I have now added here 

 and there new matter from my physiological note-book. 



I remain. Sir, 

 Bane op England, Tour obedient servant, 



Oct. 27th, 1840. AxFEED Smeb. 



The intimate or microscopic structure of bone has been the subject of 

 much investigation both in this country and abroad, yet there still appears 

 to be much scope for further discoveries. To the uninitiated the structure 

 of bone under the microscope is one of the most splendid sights possible. 

 To the initiated, though he may often have participated in the pleasure of 

 examining it, yet the beautiful arrangement never ceases to afford the 

 greatest delight. 



The best mode of preparing the sections of bone is to cut portions, of a 

 convenient thickness, with a saw, and then to mb one surface quite smooth 

 on a hone, and afterwards to polish it upon a piece of leather ; a slip of 

 glass is then to be obtained, and one or two drops of balsam of Canada are 

 to be placed on one surface : the polished side of the bone is to be put on 

 the balsam, the glass is to be heated, which melts the balsam, and causes 

 it, when cool, to fix the section firmly on the glass. The next operation is 

 to polish the opposite side of the bone, and render it sufficiently thin to be 

 translucent, which is to be effected either by grinding it upon a hone, or, 

 if the section is very thick in the first instance, by filing the bone down to 

 the requii-ed thinness; lastly, the specimen is to be polished as before. 

 Occasionally the structure is best seen by scraping down the bone, but this 

 is a tedious operation and seldom required. 



The sections by these processes are made extremely thin, and are now 

 fit for examination by the microscope. The canals of Havers are seen 

 conspicuously when the bone is moderately magnified. They are irregular 

 canals running for the most part in the direction of the long axis of the 

 bone, and frequently anastomosing with each other. They are frequently 

 seen to arise either from the external or internal margin of the bone. 



Around these canals are small irregular bodies, arranged in circles, 

 and having the surfaces parallel to the long diameter, looking towards their 

 several canals. Apart from these series of corpuscules, attached to the 

 Haversian canals is a row running round both the exterior edge of the 

 bone and the edge of the medullary cavity. These run round every 

 filament of the ceUulax tissue of bone, which, unless any portion happens 

 to be very thick, has more of the Haversian canals. 



A junction is effected between the corpuscules and the Havei-sian 

 canals, and also between the corpuscules and the margins of the bone, by 

 numerous little fine Unes which communicate in every direction with the 

 neighbouring corpuscules. These fine lines also connect the corpuscules of 



