380 SOLANACE^: 



4. Hyoscyamus (leaves) contain 0.08 per cent, of alkaloid, mostly hyoscy- 

 amine, with a fair amount of hyoscine, and only traces of atropine. It is 

 rather narcotic but is weaker than the other drugs of the group (Bastido). 



Ash, root, not more than 7 per cent. ; leaves, not more than 20 per cent. 



ACTION AND USES. Applied externally belladonna is anodyne and 

 anesthetic. Internally the activity of the peripheral terminations 

 of all the secretory nerves in the body is depressed. Dropped into 

 the eye, solutions of belladonna or atropine quickly dilate the pupil 

 and accommodation is paralyzed. Upon the heart it has a stimu- 

 lating action; toxic doses abolish the function of the cardiac muscles 

 and the heart stops in diastole. When a i per cent, solution of 



FIG. 218. Cross-section of Belladonna root. 



atropine sulphate is dropped into the eye, the pupil dilates in about 

 fifteen or twenty minutes, but takes two hours to reach the maxi- 

 mum dilation. The pupil gradually regains its power but is not 

 fully restored to normal for one or two weeks. 



An antagonist of atropine is physostigmine, which stimulates 

 the ends of the third nerve. It is not powerful enough to remove the 

 effects of atropine at once, but greatly lessens the time which the 

 eye takes to return to normal. 



Dilated pupils, dry throat, and wild cerebral symptoms are the 

 regular warnings of overdosage. In full poisoning there is a stage 

 of central stimulation followed by collapse. Dose: i to 3 gr. (0.065 



