356 
Proceedings of Royal Society of Edinburgh. [sess. 
When 0*02 grm. and upwards is given, there is marked depres- 
sion of the brain and spinal cord, but very soon (in J-J hour) the 
motor nerves begin to be impaired, and finally their excitability is 
entirely abolished. With the smaller of these doses the paralysis 
of motor nerves passes off next day, and the frog is found to be in 
a condition of greatly increased reflex excitability, but if the dose 
be 3 centigrammes or upwards it generally dies before the paralysis 
has passed off. 
Exyt. 19. — Frog, 31 grins. 
2.20. — 0’02 grm. methylmorphium chloride subcutaneously. 
2.40. — Has gradually become more and more flaccid; pupils 
extremely small. Both sciatic nerves paralysed. 
Second day. — Sitting up in its natural position. The reflex ex- 
citability is greatly increased ; pupils large. 
Third day. — Found dead. 
When the alkaloid is given subcutaneously the reflex excitability 
is never so much increased as to amount to tetanus, the reason 
being that doses large enough to cause tetanus kill the animal before 
the paralysis of motor nerves has passed off. If, however, the 
motor nerves be protected, and the methylmorphium be then injected 
into the aorta so as to reach the spinal cord at once, we get im- 
mediate violent tetanus, just as we have seen with morphine itself, 
or with codeine and other morphine derivatives. This proves con- 
clusively that methylmorphium still retains the convulsant action 
which is simply masked by its paralysing action on motor nerves. 
The following experiment may serve as an example : — 
Expt. 20. — Frog decapitated ; body ligatured, except lumbar 
nerves; right aorta tied; cannula in left aorta. 
11.10. — 0*03 grm. in 1 cub. cent, water injected into left aorta. 
At once there was rigid tetanus, which lasted till 11.21, when 
it became somewhat relaxed. 
11.25.— Each stimulation causes one tetanic spasm. 
11.34. — Response much feebler to stimulation. 
12.0. — A faint twitch on stimulation. The lumbar nerves are 
still quite excitable to electric stimulation, hence the exhaustion 
must be due to paralysis of the spinal cord. 
Two centigrammes administered in the same way gave similar 
results, but small doses such as 5 milligrammes caused depression 
