55 
of Edinburgh, Session 1866 - 67 . 
over the part in order to distinguish their existence. After death, 
if a muscular surface be exposed, these twitches will be observed 
to rarely involve the whole of one muscle, but at different times 
different muscular fasciculi ; and they may persist for more than 
thirty minutes after death. They are caused by a direct effect of 
Calabar bean on the muscular substance. This is shown by their 
occurring in muscles after paralysis of the motor nerves, by their per- 
sisting in a muscle cut out of the body, and by their non-occurrence 
in parts which have been separated by ligature from the circulation. 
9. The heart’s action is rapidly slowered and then stopped, in 
birds and mammals, by a large dose. In dogs it may diminish to 
one-half in three minutes and cease in ten. A large dose injected 
into the abdominal cavity of a frog causes rapid and complete para- 
lysis. A smaller dose causes either a gradual cessation and then 
a renewal at a diminished rate, or a gradual slowering from sixty or 
seventy to four or six beats per minute, followed by a gradual acceler- 
ation to a diminished rate varying from eight to twenty per minute. 
At this stage, and for many hours afterwards, the only signs of 
vitality are the diminished cardiac action and the power of the 
voluntary muscles to respond to galvanic and other stimulation. 
In the frog, where alone this diminution without stoppage, suc- 
ceeded by partial acceleration, has been observed, the heart may 
continue so to contract for three, and for even five days, provided 
the temperature of the apartment be as low as 50° F. After stop- 
page, galvanic stimulation may cause a renewal of its rythmical 
contraction; but this is usually lost, and unrythmical and partial 
contractions can be only excited. The heart ceases to contract in 
diastole with all its chambers full. 
10. The pneumogastric nerves retain their inhibitory power on 
the heart during the whole time from the diminution to the partial 
recovery of its action. Soon after this, however, they are paralysed ; 
and this occurs at nearly the same time as the affection of the 
motor nerves. 
11. Division of the pneumogastric nerves, or destruction of the 
medulla oblongata and medulla spinalis, does not protect the heart 
from the action of Physostigma. 
12. The lymphatic hearts of frogs poisoned by Calabar bean soon 
cease to contract. 
