1889 - 90 .] Mr Dott and Dr Stockman on Morphine. 
335 
Physiological Action of Codeine. 
(Methylmorphine C l7 H 17 NO.OH.OCH 3 ). 
The action of codeine obtained directly from opium has been 
investigated by many experimenters (see Bibliography). We 
found that artificial codeine prepared from morphine has identically 
the same action as the natural product, and hence a comparatively 
small number of experiments was sufficient for our purpose. 
Its action is exerted on the central nervous system, and has 
a close generic resemblance to that of morphine. Schroeder and 
others have pointed out that it causes an evident narcotic stage, 
followed by a condition of increased reflex excitability which 
amounts to tetanus if the dose be large enough. The narcotic 
stage is, however, shorter and much less deep than with morphine, 
and if large doses be given to animals is often hardly noticeable 
or quite absent. 
The narcotic action of codeine on man is much feebler than that 
of morphine, and only in one case (a child) has its tetanising effect 
been observed. 
Its paralysing influence on motor nerves in frogs has been 
pointed out by several observers, and is very much greater than 
that of morphine. In frogs the heart is slowed; in Mammalia blood 
pressure is not affected, and the pulse-rate only very slightly. 
This is probably due to depression of the cardiac motor ganglia 
(Schroeder). In dogs and cats it produces marked vomiting and 
diarrhoea, much more so than morphine. 
Frogs . — Our own experiments on frogs confirmed Schroeder’s to 
a large extent. We found that very small doses, such as 00013 
grm. had no apparent action at the time, although next day there 
was a very faint increase in the reflexes. Larger doses of 5 milli- 
grms. and upwards caused a characteristic stage of depression with 
diminished reflexes. This is not deep, lasts but a short time, and 
is followed by increased reflex. When the dose was 0‘01 grm. or 
more, the narcotic stage was followed by tetanus. 
Schroeder states that if as much as 2 or 3 centigrms. be given, the 
narcotic stage is never developed, but that tetanus comes on almost 
at once. This, however, depends entirely on the rate of absorption. 
We found that much larger doses (even (H)6 grm.) occasionally had 
