68 
MAMMALIAN ANATOMY 
whole coelomic cavity. Each trunk consists of segmentally 
arranged chain ganglia joined together serially by slender con¬ 
nectives. Note that the sympathetic trunks extend through the 
neck region accompanying the vagus nerves, but that there are 
only three pairs of cervical ganglia. The most anterior of these 
lies close beside the ganglion of the vagus, and the middle one is 
located in close proximity to the very large stellate ganglion, the 
most posterior of the series, immediately anterior to the first 
rib. Each stellate ganglion gives off a branch to the vagus of 
that side and another branch which joins one from the vagus to 
be distributed to the plexus of the heart. 
Note that the lower thoracic ganglia give off nerves, among 
them the greater and lesser splanchnic nerves which connect with 
the coeliac ganglion posterior to the stomach. 
Draw such details of the preparation as you are able to see clearly 
and to understand. 
B. STRUCTURE OF THE SPINAL CORD. 
i. Macroscopic Study. —With a wet section knife make a clean, 
thin transverse section of a piece of well hardened spinal cord 
(10% formalin followed by 70% alcohol has been found to give 
good results). Place one or more of these in water in a clear glass 
watch crystal and examine it over a black background with a 
dissecting microscope, for the general topography of the cord. 
For comparison examine macroscopically over a white back¬ 
ground, stained transverse sections (Lab. SI. Coll.) through 
various regions of the cord, some of which show sections also of 
the spinal ganglia. In each of these preparations note whether 
or not the dura mater is present and its relation to the nerve 
roots and ganglia, when these also are present in the section. 
Make out the following points in the general topography thus 
studied: 
The median ventral fissure and the less conspicuous median 
dorsal sulcus, both reaching nearly to the center of the section; 
the less sharply marked dorsal lateral and ventral lateral sulci, 
and the relation of these to the nerve roots. 
The section through the gray nerve substance which presents 
an H shaped area with the lumen of the canalis centralis lying 
