154 APPENDIX. [No. III. A. 



up my mind as to enable me to state the fact positively ; but, upon the 

 ■whole, alter numerous examinations of various specimens prepared in 

 this mannei*, it may be stated that there was an appearance in those 

 corpuscules immediately surrounding the canals, of its having pene- 

 trated the cavities; but, perhaps, the facts already adduced require no 

 confirmation. 



Having proved by the results of direct observation that the corp^is- 

 cules are cells, and therefore ill named corpuscules, but better cellules, 

 their use is the next point which demands our notice; but this will 

 probably be for ever theoretical. Perhaps they act the same part to 

 compact tissue of the bones as cells do to the cellular ; namely, that of 

 giving lightness without materially diminishing their strength. 



What the particular structure of the bone is between the corpuscular 

 lines and corpuscules there appears to be no means of ascertaining ; for 

 the highest power in the thinnest section only exhibits a transparent 

 homogeneous texture. 



Whether the corpuscular tubes contain blood perhaps we may also for 

 ever be ignorant, but, considering that they communicate with decided 

 blood-vessels, this opinion is far from improbable. It is certain they are 

 much too small to can-y the globules, but the opinion of their being blood- 

 vessels may receive additional weight from the fact that in bone there are 

 no canals smaller than the Haversian. 



The size of the corpuscules or cellules is about equal to two or three 

 globules of blood ; they appear for the most part broader when viewed in 

 a section parallel to the Haversian canals, than when seen in a section 

 perpendicular to them : if it is really the depth which is seen in the 

 longitudinal section of bone, it follows that these little bodies are deeper 

 than they are broad, and we have already noticed that their length is much 

 greater than their breadth. I conceive that the form of the coi-puscules 

 may be exactly given by taking a piece of wood twice as deep as it is 

 broad, and twice or three times as long as it is deep, and then rounding oflF 

 all its angles. Sections in different planes through this would present 

 every form which is observed in the corpuscules. 



Thus we have seen that the structure of bone is extremely simplified, 

 as there is a medullary cavity from which spring the corpuscular tubes, 

 and three or four layers of corpuscules or cellules around it. The same is 

 seen with regard to the exterior part of the bone. Between these two 

 layers run tubes for blood, irregular as to size, frequently anastomosing 

 with their neighbours, and having the general direction of the bony tissue 

 in which they are imbedded. 



Eadiatoiy lines are spoken of by some as existing round the Haversian 

 canals, but they have no real existence, and are only the corpuscular canals 

 or lines seen deep in the section, and out of focus ; and they are only to 

 be seen when these lines are opaque, and the section thick. 



The ceUular tissue of bone has no Haversian canals ; for there the cells 

 have the same relation to the bony structure of each ceU as the Haversian 

 canal has to the bone immediately surrounding it. 



With regard to the laminse of bone which have been described by 

 other authors, they appear to me to exist only as the result of the inge- 

 nuity of the anatomist, for we see that the shaft of a long bone consists 

 of a large medullary cavity, with a series of corpuscules and corpuscular 



