256 
LIFE. IN ITS HIGHER FORMS. 
In like manner every lateral nerve is double, arising by 
two distinct roots, the one from the motor, the other from 
the sensitive tract. 
Besides these, there are series of nerves, extensively 
ramified, which do not originate from either brain or spinal 
column, but from scattered ganglia situated in various parts 
of the body, and destined to supply those important organs 
whose motions are independent of the will, and which 
are therefore distinguished as the organic or vegetative 
system. 
The blood is, in every case, composed of red “globules” 
or (more properly) disks, suspended in a watery fluid. 
It circulates through two series of vessels, which ramify 
to every part of the body. The one series — that of the 
veins — receives the assimilated nutriment from the diges- 
tive system, and conveys the blood, so reinforced, but 
exhausted of its oxygen, to the heart, a great muscular 
chamber, which alternately contracts and expands without 
intermission. By these movements, the contained volume 
of blood is urged forward, in whole or in part, to the 
lungs, or (in such animals as are aquatic) to the gills, 
where it is brought into proximity with fresh oxygen, 
either from the inhaled air or water. This element 
readily combines with the blood through the excessively 
attenuated coats of the vessels, and revivifies it, restoring 
at once its brilliant red hue. Thus renewed, the vital 
fluid is returned to the heart, whence it is forced into 
the other series of vessels called arteries, which carry it 
forward to all parts of the body, and at length, uniting 
with the veins by excessively minute tubes called capilla- 
ries, situated at the circumference, and having built up 
