a oe 
SSI 
Different Animals, &e, BIR 
2. The cineritious and medullary substances 
are the essential parts of the nervous system, the 
coats or membranes of the encephalon, spinal 
marrow and nerves being given them merely for 
protection and not contributing directly either to 
sensation, or motion. * 
3. Nervous matter is distributed to many 
points, where we cannot demonstrate its pre- 
sence to the eye and wheré we can only infer its 
existence from their sensibility. We cannot 
prick the skin with the smallest instrument, with. 
out exciting pain; whence it is evident, that there 
is nervous matter in every point of the skin, 
though we have no other means of proving it. 
4- The blood vessels had evidently possessed 
the power of circulating the blood in this mon. 
Strous fetus and, though it was much inferior in 
size to its fellow-twin, its growth had proceeded 
to a certain extent, and bone, skin, cellular mem 
brane, ligament, cartilage, intestine; &e had been 
formed: Now I do not admit any power as 
capable of giving energy to the muscular fibres of 
the arteries and veins, except the vis nerved, Or 
nervous power. 
Tam of opinion, that no such power exists in 
muscular fibres as a vis insi/a, or inherent power, 
distinct from, or independent of, a nervous pow- 
er, The experiments and arguments, adduced by 
VOL, Vv. BB 
