340 VEGETABLE DRUGS 



partly to action upon the motor tract of the brain, and 

 finally proceed from direct local stimulation of the motor 

 nerve endings and muscles. 



Action Upon Horses. — Three grains of morphine, injected 

 subcataneously, occasion sometimes drowsiness, and at 

 other times produce no visible 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 rythmical manner about the stall. The pupils 

 are dilated. Large doses (12 grains) are followed by in- 

 creased excitement, sweating, muscular rigidity and trem- 

 bling; while still larger doses (four drachms of the extract 

 of opium) cause violent trembling, convulsions, insensibility 

 to pain and external irritation, without coma ; or (morphine, 

 gr. 36 under the skin) stupor for several hours (3 hours), 

 dilated pupils and blindness, followed by delirium and rest- 

 lessness, continuing for a longer time (7 hours) and ending 

 in recovery. Horses have recovered from an ounce of 

 opium, but 2J ounces of the drug, and 100 grains of mor- 

 phine 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 Upon Ruminants. — These animals are comjmra- 

 tively insusceptible to opium. Ounce doses of the drug 

 cause, in cattle, restlessness, excitement, hoarse bellowing, 

 dry mouth, nausea, indigestion and tympanites. Sheep are 

 affected in much the same manner. One to two drachms of 

 morphine have led to fatality in cattle. Fifteen to thirty 

 grains of the alkaloid comprise a lethal dose for sheep. 

 Swine are variously influenced; sometimes excited, some- 

 times dull and drowsy. 



Action Upon Birds. — Birds, as represented by chickens, 

 ducks and pigeons, are exceedingly insusceptible to opium. 



