CODEINE. 
§ 37 6 -] 
317 
aqueous solution—the iodine particle does not become surrounded with 
fine crystals. 
§ 376. Effects. —The physiological action of codeine on animals has 
been investigated by Claude Bernard, Magendie, Crum Brown and 
Fraser, Falck, and a large number of others. 1 It has also been ad¬ 
ministered to man, and has taken in some degree the place of morphine. 
Claude Bernard showed that, when given to dogs in sufficient quantity 
to produce sleep, the sleep was different in some respects from morphine 
sleep, especially in its after-effects. Thus, in his usual graphic 
way, he describes the following experiment :—“ Two young dogs, ac¬ 
customed to play together, and both a little beyond the average size, 
received in the cellular tissue of the axillae, by the aid of a subcutaneous 
syringe, the one 5 centigrammes of morphine hydrochloride, the other 
5 centigrammes of codeine hydrochloride. At the end of a quarter of 
an hour both dogs showed signs of narcosis. They were placed on their 
backs in the experimental trough, and slept tranquilly for three or four 
hours. When the animals woke, they represented a striking contrast. 
The morphine dog ran with a hyena-like gait ( demarche hyenoid), the 
eyes wild, recognising no one, not even his codeine comrade, who vainly 
bit him playfully, and jumped sportively on his back. It was not until 
the next day that the morphine dog regained his spirits and usual 
humour. A couple of days after, the two dogs being in good health, I 
repeated the same experiment, but in a reverse order—that is to say, I 
gave the codeine to that which previously had the morphine, and vice 
versa. Both dogs slept about as long as the first time ; but on waking 
the attitudes were completely reversed, just as the administration of the 
two substances had been. The dog which, two days before, after having 
been codeinised, woke lively and gay, was now bewildered and half 
paralysed at the end of his morphine sleep ; whilst the other was wide 
awake and in the best spirits.” 
Subsequent experimenters found what Bernard does not mention, 
viz. that codeine produced epileptiform convulsions. Falck made some 
very careful experiments on pigeons, frogs, and rabbits. To all these 
in high enough doses it was fatal. Falck puts the minimum lethal dose 
for a rabbit at 51-2 mgrms. per kilo. Given to man, it produces a sleep 
very similar to that described by Claude Bernard—that is, a sleep which 
is very natural and does not leave any after-effect. Therefore it is 
declared to be the best alkaloid of a narcotic nature to give when 
lengthened slumber is desired, more especially since it does not con¬ 
fine the bowels, nor has it been found to produce any eruption on the 
skin. Before it has a full narcotic effect, vomiting has often been 
excited, and in a few cases purging. The maximum dose for an 
1 Ann. Cham. Phys. [5], xxvii. 273-298 ; also, Journ. Cham. Soc., No. ccxliv., 
1883, p. 358. 
