36 
MAMMALIAN ANATOMY 
mal). Such sections should be made by hand with a section 
knife, the piece of cartilage being held firmly between two pieces 
of pith, through which the knife passes in making the section. If 
several such sections are made rapidly and allowed to fall into a 
dish of the salt solution, among these, one will be likely to be thin 
enough to use. 
Examine under both low and high power, selecting particu¬ 
larly the growing region near the periphery. Note that the 
rounded cartilage cells are arranged in groups, each cell and each 
group surrounded by a capsule, which in its outer boundary blends 
with the capsules of other groups, thus contributing to a hyaline 
intercellular matrix. 
Study permanent preparations (Lab. SI. Coll.) of stained 
sections of hyalin cartilage to demonstrate the above-mentioned 
structures. Record your observations by suitable drawings. 
For comparison study and draw sections (Lab. SI. Coll.) 
of fibro cartilage ( e.g ., intervertebral cartilage). Note that the 
cells are of the typical cartilage nature with hyalin capsules, but 
that the intercellular substance includes numerous bundles of 
collagenous fibers like those of connective tissue. 
Similarly study and draw sections (Lab. SI. Coll.) of elastic 
cartilage (e.g., the cartilage of the external ear). Note that in the 
hyalin matrix which lies between the groups of typical cartilage 
cells, there is a reticulum of elastic strands with the highly 
refractive appearance characteristic of these. 
2. Bone. 
Study a transverse section (Lab. SI. Coll.) through the dense 
bone which forms the shaft of a long bone of some small mammal, 
decalcified and stained. Study under low power for general 
topography, noting the periosteum which forms its outer covering 
and the mass of cells of various types which fills its marrow cavity. 
Note that in the bony tissue itself the intercellular substance 
consists of systems of parallel lamellae which follow the direction of 
(i) the outer surface of the bone (peripheral lamellae); (2) the 
boundary of the marrow cavity (medullary lamellae); and (3) the 
Haversian canals .through which the blood vessels and nerves reach 
the various parts of the bone (Haversian systems of lamellae); and 
