512 CALABAR BEAN 



membranes. It relieves obstruction by stimulating the 

 neuro-muscular apparatus of the stomach and intestines. 

 Given by the mouth, or applied locally, it contracts the 

 pupil and slightly diminishes intraocular pressure effects 

 due to stimulation of the third nerve, or of the circular 

 muscular fibres of the iris, or of both. This myosis results 

 in horses in twenty-five to thirty minutes ; and in less than 

 half that time in carnivora ; but is not produced, even by 

 conjunctival injection, in birds, frogs, and fishes. 



Excessive doses after this stimulation paralyse muscular 

 fibre, especially the unstriped variety, and also motor nerves. 

 Moderate doses have little effect on voluntary muscles, but 

 full doses induce local twitching, best marked at the elbow 

 and stifle, followed by general trembling and spasmodic 

 contractions ; at the same time the animal sweats, salivates, 

 blows, strains, and discharges faeces and urine, and all his 

 organs provided with unstriated muscle participate more or 

 less in the clonic convulsions. Its stimulant effects on 

 motor nerve-endings and on unstriped muscle in part 

 explain its action on the circulation. Small to moderate 

 doses contract minute blood-vessels, and reduce the force 

 and frequency of the heart movements. Kaufmann mentions 

 that a single full dose reduces the pulse of the dog from 100 

 to 40 beats per minute. Eraser believes that its action on 

 the heart is threefold (1) it stimulates peripherally the 

 cardio-inhibitory branches of the vagus ; (2) it depresses 

 the cardiac motor ganglia ; and (3), in large doses, it 

 paralyses the cardiac muscular fibres. Respiration is 

 temporarily quickened, apparently from stimulation of 

 the vagi in the lungs, but in fuller doses is slowed from paresis 

 of the medullary respiratory centre. Moderate doses 

 stimulate the liver, the involuntary muscles of the bronchial 

 tubes, so lessening their calibre, also the muscular fibres of 

 the uterus, and bladder, and increase gastric and intestinal 

 peristalsis, quickly causing free and fluid evacuations from 

 the bowels, and besides, inducing in man and carnivora 

 retching and vomiting. The secretion of saliva, sweat, and 

 mucus is increased. 



Poisonous doses disturb voluntary motility and paralyse 

 the spinal cord. Hence results the characteristic curare- 



