6o 
MAMMALIAN ANATOMY 
surrounded by a clear circumnuclear zone, and containing always a 
deeply stained nucleolus. Examine the various cytoplasmic 
processes and note in general the presence of tigroid bodies in 
these. A single process, the axone or neurite does not possess 
these and may thus be distinguished from the remaining processes, 
the dendrites. Neuro-fib rillae extend throughout all the processes. 
Draw a good typical cell , showing the above named parts. 
2. Golgi preparations of nerve cells in sections of the cerebral 
and cerebellar cortex (Lab. SI. Coll.). These preparations, in 
which the neurones have been rendered black by the action of 
silver nitrate, are particularly for the purpose of showing the forms 
of the various cells and the course of their branches. They are 
thick preparations and do not as a rule permit the use of the high 
power objective. In some cases the axone may be distinguished 
from the dendrites by its smoother surface and its right-angled 
form of branching (cl. pictures of nerve cells in any good text-book 
of histology). Look particularly in the cerebral cortex for the 
characteristic pyramidal cells and in the cerebellar cortex for the 
Purkinje cells with their flask-shaped perikarya and enormous 
tree-like dendrites. Draw one or more good typical cells , and 
identify the types drawn by reference to some text-book of histology. 
3. Sections through the cerebral and cerebellar cortex stained 
to show the details of the cells of the different layers in situ (Lab. 
SI. Coll.). Study as many such sections as the time and material 
permit, identifying the layers and their characteristic cells by use 
of any good reference or text-book of histology. Note particularly 
the characteristic pyramidal cells of the cerebral cortex, and the 
Purkinje cells of the cerebellar cortex. Draw as much detail as 
you are able to identify and understand. 
B. NERVE FIBERS, THE PROLONGED PROCESSES OF 
NERVE CELLS. 
From the study of the following preparations note that there 
are two kinds of fibers, in both of which the essential part is the 
conspicuous, slender, non-nucleated column of protoplasm, known 
as the axis cylinder, which lies on the middle of the fiber and is in 
reality the much elongated process of some nerve cell. The 
