DBUGS ACTING ON THE CIRCULATION 33 



which prove detrimental to the system. This line of treat- 

 ment is pursued in uraemia, haemoglobinsemia and lymph- 

 angitis. Venesection, saline infusions, hypodermoclysis and 

 enteroclysis alter the character of the plasma and often have 

 a life-saving value. (See p. 696-703.) 



(b) T he Red Corpuscles. — The so-called blood tonics, or 

 hcematinics influence the red corpuscles, increasing their 

 number and content of haemoglobin when there is a defi- 

 ciency of either. The effect upon the augmentation of haemo- 

 globin is more marked. 



H^MATINICS. 



Iron and its salts Corrosive sublimate 



Arsenic Potassium permanganate 



Copper salts Manganese dioxide 



The first two avR immensely superior to the others in 

 blood-making properties. Iron especially favors the forma- 

 tion of haemoglobin ; arsenic increases the number of red 

 corpuscles. 



(c) White Corpuscles. — It is possible experimentally to 

 arrest purulent exudations caused by irritation and inflam- 

 mation when quinine is introduced into the blood or applied 

 locally to blood vessels. This happens because quinine — 

 like other poisons to amoebae — prevents the amoeboid 

 movement or migration (diapedesis) of leucocytes through 

 the vessel walls. Unfortunately it is impossible to give 

 large enough doses in practice to realize such favorable 

 results in inflammatory disorders. An euormons increase 

 of leucocytes (leucocytosis) occurs in acute diseases accom- 

 panied by a local exudative process, and also in leukaemia, 

 etc. Arsenic, and in some cases quinine, appear to reduce 

 the leucocytosis, and in leukaemia seem to thus aid recovery. 



II.— Drugs Acting on the Heart. 



The mechanism controlling the heart, which is influenced 

 by drugs, is as follows : 



1. Heart-muscle and ganglia. 



2. Inhibitory apparatus, including the vagus nerve roots 



