328 
Proceedings of Royal Society of Edinburgh. 
We have seen that a certain amount of morphine is necessary to 
cause the tetanus, and therefore (1) we may suppose that the 
nerve cells have a special affinity for the morphine, that they 
abstract it from the blood and store it up, and that it is only when 
they have absorbed and retained sufficient to bring about the 
requisite changes that tetanus comes on • or (2) we may suppose 
that the morphine is not stored up in the nerve cells, hut that, 
passing frequently through them dissolved in the blood, it gradually 
brings about changes which result in tetanus. 
With regard to the action of morphine on motor nerves great 
differences of opinion have been expressed by different experi- 
menters. The older observers, finding that the motor nerves were 
considerably depressed in electric irritability at the end of the 
poisoning, concluded that the alkaloid had a directly depressing 
effect on them. Witkowski, however, is of opinion that this is due 
to exhaustion after the prolonged tetanus, for on dividing one 
sciatic nerve, and then administering a large dose of morphine, he 
found that the divided nerve had remained perfectly excit- 
able, while the undivided nerve was more or less depressed. 
Vulpian also found that in rabbits the motor nerves remain 
unaffected. 
We have repeated Witkowski’s experiment frequently, with a 
result similar to his, hut we are of opinion that his conclusion is 
erroneous. The result must he due to the morphine not reaching 
the terminations of the motor nerves in sufficient quantity to 
paralyse them markedly, for we found when we injected a solution 
into the aorta, so as to make sure of it reaching the terminations of 
the motor nerves, that these were paralysed. The amount required 
is, however, large, and the end-organs of motor nerves are certainly 
not very sensitive to the action of morphine. The following is one 
of the experiments. 
Expt. 3. — Frog pithed. Sciatic nerves excitable well at 200 mm. 
Du Bois Beymond Coil. 
12.35. — 0*06 grm. morphine hydrochlorate in If cub. cent, water 
injected into abdominal aorta just above bifurcation. 
At once there was marked diminution in the excitability of 
sciatic nerves. 
12.45. — Sciatic nerves excitable only to strongest currents. The 
