PHYSIOLOGICAL RELATIONS OF BELLADONNA 361 



of the two drugs are combined, and therefore atropine 

 should hd given with caution in the treatment of opium 

 narcosis, so as not to aggravate the already existing central 

 nervous depression, particularly of the respiration. Mor- 

 phine relieves pain, causes sweating, and contracts the 

 pupil centrally. Atropine dilates the pupil, produces dry- 

 ness of the skin, and depresses the functions of sensory 

 nerves through its peripheral action. Atropine antagonizes 

 physostigma in so far as the latter stimulates the peripheral 

 oculomotor nerve fibres, the vagi, diminishes blood pres- 

 sure, depresses the respiratory centres, and stimulates the 

 unstriated muscle of the intestines, and the secretions of 

 the stomach, bowels and bronchial tubes. 



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

 stimulates secretory nerve terminations in the sweat and 

 salivary glands, the peripheral oculomotor filaments, and 

 the nerve endings in the involuntary muscle of the heart, 

 stomach, intestines and uterus. Atropine counteracts the 

 influence of aconite and muscarin (the poison of fungi) upon 

 the heart, and the action of the latter principle in producing 

 spasm of the pulmonary vessels. 



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 fre- 

 quent micturition. These symptoms are succeeded, in 

 fatal poisoning, by fall of temperature, retention of urine, 

 muscular weakness, staggering gait, partial anaesthesia, 

 convulsions and paralysis (one preponderating 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 physiological 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 



