284 VEGETABLE DRUGS 



neurones of the cord so that the motor centres respond more acutely to 

 sensory stimuli. 



A medicinal dose of atropine stimulates, while morphine depresses, 

 the brain, respiratory functions, and intestinal peristalsis. This antag- 

 onism ceases when poisonous doses of the two drugs are combined, and 

 therefore atropine should be given with caution in the treatment of 

 opium narcosis, so as not to aggravate the already existing central nervous 

 depression, particularly of the respiration. Morphine relieves pain, 

 causes sweating, and contracts the pupil centrally. Atropine dilates the 

 pupil, produces dryness of the skin, and depresses the functions of sen- 

 sory nerves through its peripheral action. Atropine antagonizes 

 physostigma in so far as the latter stimulates the peripheral oculomotor 

 nerve fibres, the vagi, diminishes blood pressure, depresses the respiratory 

 centres, and stimulates the unstriated muscle of the intestines, and the 

 secretions of the stomach, bowels and bronchia] tubes. 



Atropine is antagonistic — in part — to pilocarpine, which stimulates 

 secretory nerve terminations in the sweat and salivary glands, the peri- 

 pheral oculomotor filaments, and the nerve endings in the involuntary 

 muscle of the heart, stomach, intestines and uterus. Atropine counteracts 

 the influence of aconite upon the heart. 



Toxicology. — Toxic doses of belladonna cause in animals dryness of 

 the mouth, increased frequency of the pulse and respiration, elevation 

 of temperature, dilation of the pupil and partial blindness, restlessness, 

 nervousness, delirium, twitching of the muscles (occasionally erythema), 

 and frequent micturition. These symptoms are succeeded, in fatal poi- 

 soning, by fall of temperature, retention of urine, muscular weakness, 

 staggering gait, partial anesthesia, convulsions and paralysis (one pre- 

 ponderating over the other), weak, slow, irregular respiration, feeble, 

 rapid pulse, paralysis of the sphincters, stupor and death. Death occurs 

 mainly from asphyxia, but is due in part to cardiac failure. The physio- 

 logical test consists in placing a drop of the urine (secreted by the 

 poisoned animal) into the eye of a healthy animal, when mydriasis should 

 follow if the case be one of belladonna poisoning. Three-quarters of a 

 grain of atropine under the skin has proved fatal to dogs. Two grains 

 of atropine produce mild toxic symptoms in the horse. Small dogs are 

 slightly poisoned by gr. 1/80 of atropine; medium sized dogs by gr. 1/60 

 given hypodermaticalljr. Cattle are as susceptible as horses, but neither 

 are so readily influenced by the drug as carnivora. The pulse in dogs is 

 greatly accelerated, sometimes as high as 400, while the pulse rate of the 

 horse is not generally more than doubled. Rodents, as guinea pigs and 

 rabbits, and pigeons, are particularly insusceptible to belladonna, in 

 regard to its effect upon the pupil, circulation, etc. 



The treatment of poisoning includes the use of the stomach tube, 

 emetics, bromides, alcohol or ether in the stage of excitement ; and cardiac 

 stimulants, as caffeine, and artificial respiration in the later depression. 

 Also external heat and general faradism. 



Post-Mortem Appearances. — These are not generally characteristic, 

 except of asphyxia. The blood is dark and poorly coagulable. There is 



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