196 Wyman on the Cancelli of Bones. 
the strongest laminze run through the structure in those direc- 
tions in which the bone has naturally to sustain the greatest 
pressure.” (Vol. I. p. 75.) But he does not adduce a single 
- instance in illustration of his general proposition. 
Bourgery and Jacob, to whom the merit belongs of first 
calling attention to the subject, have recognized its interest, 
and have shown that there exists in several of the bonesa 
definite relation between the direction of the cancelli and the 
weight that the bones, of which they form a part, are destined 
to sustain. Their description of the neck of the thigh bone, 
it is believed, will be found on comparison to be incorrect. 
In the lower extremity of the femur, and in both extremities 
of the tibia, in the astragalus and os calcis, the cancelli are 
accurately described and figured. Mr. F. O. Ward, in his 
Outlines,' as regards the structure of the bones of the tarsus, 
simply follows the descriptions of Bourgery and Jacob. He 
has attempted a description of the mechanical structure of the 
neck of the thigh, but as will be shown further on, there is 
sufficient reason for regarding his description, as well as that 
of the last mentioned authors, incorrect in its details. These 
constitute the only references which I have been able to find, 
bearing upon the subject of this communication. 
Before proceeding to the detailed description of individual 
parts, it may be proper to state, in general terms, the inferences 
which are deducible from the structures of the various bones; 
and, more especially, from those which assist in maintaining 
the body in its erect position ; — there are two: 
l. The cancelli of such bones as assist in supporting the 
weight of the body are arranged either in the direction of that 
weight, or in such a manner as to support and brace those. 
cancelli which are in that direction. In a mechanical point 
of view they may be regarded in nearly all these bones as & 
series of “studs” and “ braces." 
2. The direction of these fibres in some of the bones of the 
human skeleton is characteristic, and, it is believed, has & 
1 Outlines of Human Osteology, by F. O, Ward. London: 1838. 
