No. IV.] APPENDIX. 157 



after six weeks, had made no effort at reparation, but no difference could 

 be detected. 



A section of a femur was examined, in which the head of the bone was 

 affected by scrofula, but no change could be detected in the cellules. 



A transverse section of enlarged femur had the cellules in the enlarged 

 part, but in this case the canals of Havers did not run in the direction of 

 the long axis of the bone, but ran from the exterior edge. 



The structure of bone and that of the cellules have been examined in 

 numerous specimens of recent bone from different parts of the body. 

 The long, the round, the flat, the sesamoid bones, have all received their 

 share of attention, and these, with macerated bones, mummies' bones, bones 

 altered by chemical agents, diseased bones, and ossifications connected 

 with cartilage or bone, possess these cellules. 



The bones of animals and of birds which have been examined also 

 possess them. The bones of some fish, as the sturgeon and porpoise, and 

 the ossific plates or the skin on the former, agree in possessing these 

 cellules. Even the cartilaginous fishes are not destitute of them. 



The structure of bone is not only such at the present moment, but has 

 been the same from the earliest period, for the mighty ichthyosaurus, the 

 tyrant of the water in former ages, and the vast mastodon, the giant of the 

 land, possessed these cellules. Although six thousand years had elapsed 

 before the microscopic structure of bone was made known to the anatomist, 

 yet in every age, in every country, geological and antiquarian researches 

 have revealed that the same structure has existed. The imperfection of 

 our instruments has been the cause of our previous ignorance, and doubt- 

 less there is now ten times more to be learned than is already known. 



In every case where the corpuscules or cellules exist, they can be 

 distinctly perceived to be hollow. Let, therefore, the universality of this 

 fact be the only apology for its communication. 



For the following measurements I am indebted to the kindness of 

 Mr. Bowerbank : 



Haversian canals. 



Small. Large. 



3^3 jfe in diameter. 



Corpuscules or cellules seen in a transverse section. 



One of the largest. One of the smallest. 



Diameter ^ Length ^ . Diameter ^^ . Length 



Longitudinal section. 



One of the largest. One of the smallest. 



Diameter ^4 Length -^ . Diameter ^Vo . Length |- 7 - 



No. IV. 

 PHOTOGENIC DRAWING. (' Literary Gazette,' May 18, 1839.) 



VARIOUS have been the methods detailed for the preparation of paper 

 which can be acted upon with facility by the powerful agency of the light 

 from the sun; yet, notwithstanding all that has been written on this 



