PHYSICAL anv LITERARY. 339 
by means of their connexion and fympa- 
thy with the brain and {pinal marrow, 
deftroy or prevent, through the whole 
nervous fy{tem, the operation of that 
power upon which depends fenfation and 
motion in the bodies of animals. 
(g) SINCE opium applied to the abdo- 
minal mufcles of a frog, deprived of its 
brain and fpinal marrow, does not de- 
ftroy the motion of the heart fo foon, as 
when it is applied to the abdominal muf- 
cles of a frog whofe brain and {pinal mar- 
row are intire, (N° 6. and 7.), it follows, 
that the brain and fpinal marrow, and 
- confequently the nerves derived from 
them, have a greater influence than any 
other part of the animal fyftem, upon the 
motion of the heart. 
(r) Or1um does not only deftroy the 
moving power of the mufcles of animals 
by intercepting the influence of the brain 
and fpinal marrow, but alfo by unfitting 
the mufcular fibres themfelves, or the ner- 
vous power lodged in them for perform- 
ing its office: Otherways a folution of o- 
pium, when applied tothe abdominal muf- ° 
cles 
