1889 - 90 .] Mr Dott and Dr Stockman on Morphine. 327 
Hence it is by no means a necessary consequence of the action of 
morphine that depression succeeded by tetanus should occur. The 
following experiment shows this decisively. 
Expt. 2. — The brain of a frog was destroyed. Next day it had 
recovered from the pithing. A ligature was passed round the 
lumbar region, excluding the lumbar nerves ; the right aorta was 
tied ; a cannula was inserted into the left aorta. 
11.40. — 0’035 grins, morphine hydrochlorate in 1 cub. cent, water 
was injected into the cannula. At once there was rigid tetanus. 
11.42. — Another tetanic spasm. 
11.44. — Having frequent spontaneous rigid spasms. 
12.30. — The spasms have continued, but are gradually getting 
feebler. 
12.45. — Quite exhausted. No response on stimulation. 
It is necessary to tie the vessels in the lumbar region to ensure 
that sufficient of the morphine solution reaches the cord at once, 
and also (although this is not of such importance) to protect the 
motor nerves from the depressing influence of the morphine. If 
this precaution be neglected the experiments never succeed so well, 
as the greater part of the morphine, instead of going to the spinal 
cord, gets distributed over the whole body. Tetanus generally 
appears in such cases, but rather late, although never nearly so late 
as when the morphine is given subcutaneously. 
In the present state of our knowledge it is useless even to 
speculate as to what changes morphine brings about in the nerve 
substance of the cord. Small amounts of the alkaloid coming in 
contact with the grey nerve cells interfere with their vitality 
and chemical changes only in so far as to inhibit or depress their 
proper activity, whereas larger amounts cause much more profound 
changes, apparently leading to irregular and violent chemical action, 
which leads to similar irregular and violent discharges of nerve 
energy, followed by extreme exhaustion. During the first condition 
the cells are more or less incapable of conducting impulses or acting 
reflexly, whereas in the second they are completely changed in these 
respects, and respond vigorously to the slightest impression. It is 
impossible to characterise the changes more definitely. 
The delay in the tetanus when morphine is given subcutaneously 
or by the stomach can be accounted for, however, in two ways. 
