360 VEGETABLE DRUGS 



of belladonna, and an artificial glaucoma may be thus 

 produced. 



Elimination. — Belladonna is probably eliminated en- 

 tirely by the kidneys. 



Summary. — It will be observed that belladonna, gener- 

 ally speaking, first stimulates and then depresses the nerve 

 centres, while it chiefly paralyzes the motor nerve termiua- 

 tious, including the inhibitory (vagus and splanchnic), the 

 secretory (chorda tympani, etc.), and, to a less extent, the 

 sensory nerves. Secondaiy depression of the cerebrum is 

 not so profound as that of the great medullary centres, 

 especially the respiratory centre, and there is sometimes a 

 slight and brief stimulation of the motor nerves of the 

 smooth muscles, viz., vagus, splanchnic, and possibly vaso- 

 motor nerves. 



Full medicinal doses depress the peripheral filaments 

 of the inhibitory and secretory nerves, and those of the 

 unstriped muscles, lessen the functional activity of the 

 voluntary motor system, and, to a less degree, that of the 

 afferent nerves. The pulse becomes quickened because of 

 paralysis of the peripheral vagus endings and stimulation of 

 the heart or its ganglia; the blood tension is aiigmented 

 because of the increased cardiac action and stimulation of 

 the vasomotor centres; and the respiration is accelerated 

 because of excitation of the respiratory centres. fThe 

 temperature is elevated owing to the circulatory exaltation 

 and stimulation of the heat-producing centres. Slight 

 delirium may be present from the exciting action of the 

 drug upon the cerebral motor centres. 



The spinal cord is unaffected by therapeutic doses. 

 Locally applied, belladonna is a direct paralyzant to nerves, 

 muscles, vessels and cells. 



PHYSIOLOGICAL BELATIONS OF BELLADONNA TO OTHER DRUGS. 



A medicinal dose of atropine stimulates, while morphine 

 depresses, the brain, respiratory functions, and intestinal 

 peristalsis. This antagonism ceases when poisonous doses 



