76 



CIRCULATORY STIMULANTS 



take place and be due either to direct irritation of the mucosa of the 

 stomach or to a direct stimulation of the vomiting center after ab- 

 sorption to such an extent that small additional doses will cause 

 emesis. This shows that it is time to stop its administration in order 

 to avoid cumulative action. ; ; 



Fig. 8. — Action of digitalis. Combination of tlierapeutic stage with beginning 

 of intermediate stage; eliaracterized by sliglit irregularity and exaggerated 

 inhibition. Note irregular length and increased space between strokes, 

 showing irregularity of the heart's action preceding the toxic stage. 



(Reproduced, by permission, from Pittenger's Biocheraic Drug Assay Metliods. Publislied 

 by P. Blaltiston's Sons and Co.) 



Fig. 9. — Action of Digitalis. Extreme inhibition and irregularity. 



(Reproduced, by permission, from Pittenger's Biochemic Drug Assay Methods. Published 



by P. Blakiston's Sons and Co.) 



It may cause diarrhea either by direct local irritant action upon 

 the walls of the intestines or by stimulating the walls to increased 

 peristalsis. It is therefore seen that whatever action is exerted upon 

 the digestive tract is not desired. 



