HISTOLOGY OF SKELETAL TISSUES 
37 
that there are (4) systems of lamellae irregularly placed filling in the 
angles between the other systems (interstitial lamellae). Note 
that the lines of bone cells indicate the boundaries of adjacent 
lamellae. 
Under the high power study the details of the bone cells, the 
flattened, nucleated bodies of which occupy crevices or lacunae 
between the lamellae, while the intricately branching cytoplasmic 
processes project into minute canals (canaliculi) which traverse 
the thickness of the lamellae and thus make possible an actual 
anastomosis of the branches of neighboring cells. (Schmorl’s 
method of staining which renders the bone cells reddish purple 
and the lamellae yellow, is especially good for the study of these 
details.) 
For comparison study under both low and high power an 
unstained dry transverse section through the shaft of a long bone 
(Lab. SI. Coll.). Note that the method of preparation has 
removed all of the soft parts so that the Haversian canals, lacunae, 
and canaliculi appear as empty spaces. 
Examine a longitudinal section through the shaft of a long 
bone, unstained dry preparation (Lab. SI. Coll.), and identify 
from this new point of view the structures already studied in the 
transverse sections. 
Record the above mentioned facts by drawings (1) of a sector of a 
transverse section passing from the periphery of the bone to the 
marrow cavity , showing the various systems of lamellce; (2) of three 
adjoining lamellce with lacunce and canaliculi as seen under the 
high power; and (3) of a few bone cells showing the details of their 
branches. 
Study a longitudinal section through developing bone, showing 
the formation of bone from cartilage (Lab. SI. Coll.). Study first 
with the naked eye or with a dissecting microscope and note that 
the section passes through the cartilaginous head of a long bone 
which is undergoing ossification. Draw on a large scale an outline 
of the whole section and fill this in with as many of the details of 
structure as you are able to identify in the following microscopic 
study. 
Under low power study the various regions, beginning with the 
typical hyalin cartilage. Note the arrangement of the cartilage 
