OPIUM AND MORPHINE 269 



Action on Horses. — Three grains of morphine, injected subcutane- 

 ously, occasion sometimes drowsiness, and at other times produce no vis- 

 ible effect. Four to six grains^ given in the same way, cause restlessness, 

 a rapid pulse, and moisture of the skin. The animal paws the ground 

 and walks in a rhythmical manner about the stall. The pupils are 

 dilated. Large doses (12 grains) are followed by increased excitement 

 aggravated by noises, sweating, ptyalism, muscular rigidity, staggering 

 gait, trembling and delirium; while still larger doses (four drams of the 

 extract of opium) cause violent trembling, convulsions, insensibility to 

 pain and external irritation, without coma; or (morphine, gr. 36 hypo- 

 dermically), rarely, stupor for several hours (3 hours), dilated pupils and 

 blindness, followed by delirium, and restlessness, continuing for a longer 

 time (7 hours) and ending in recovery. Horses have recovered from an 

 ounce of opium, but 2^2 ounces of the drug, and 100 grains of morphine 

 have proved fatal. The action of opium upon the horse differs from 

 that upon man and dogs in the more frequent occurrence of restlessness 

 and motor excitement due -to stimulation of the cerebral and spinal 

 motor centres ; and in dilatation instead of contraction of the pupil. 

 The rationale of the latter phenomenon has not been discovered. 



Action on Ruminants. — These animals are comparatively insuscep- 

 tible to opium. Ounce doses of the drug cause, in cattle, restlessness, 

 excitement, hoarse bellowing, dry mouth, nausea, indigestion and tympa- 

 nites. Sheep are affected in much the same manner. One to two drams 

 of morphine have led to fatality in cattle. Fifteen to thirty grains of 

 the alkaloid kill sheep. Swine are variously influenced; sometimes ex- 

 cited, sometimes dull and drowsy. 



Action on Birds. — Birds, as represented by chickens, ducks and 

 pigeons, are exceedingly insusceptible to opium. This is chiefly due to 

 the slow absorption from the crop. Pigeons cannot be given enough 

 opium by the mOuth to cause death, but 8 to 10 grs. of morphine by the 

 mouth, or 2 or 3 grs. hypodermatically, will prove fatal. The toxic symp- 

 toms in birds are exhibited by unsteadiness, difficult breathing and fail- 

 ure of respiration, convulsions and death. The pupils are unaffected, 

 and sleep does not ensue. 



Action on Dogs. — When 8 or 10 grains of morphine are given to 

 a moderately sized dog, coma comes on, from which the animal may re- 

 cover. One half a grain injected under the skin of a dog weighing 25 

 lbs., causes nausea, vomiting and often purging (not occurring in man), 

 sleep deepening into coma, contracted pupils, and shallow breathing; the 

 condition lasting for several hours and''followed by recovery. Opium rare- 

 ly exerts an hypnotic action upon cats, but rather motor excitement. Lethal 

 doses (average, l/6 grain of morphine sulphate subcutaneously to the 2.2 

 pounds, live weight, for dogs; 2 to 3 grains sometimes kill small dogs), 

 increase the frequency of the pulse, cause vomiting, unsteadiness, con- 

 tracted pupils, motor exciteipent, as twitching of the limbs, follo^^ed by 

 coma, respiratory failure and death. Recovery from full doses of opium 

 is accompanied in dogs by general physical and mental depression and 

 'lassitude, as in man. There are muscular weakness, loss of natural 



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