VASOCONSTRICTORS 99 



often useful by lowering blood pressure and allaying excite- 

 ment and movement. 



VASO-CONSTRICTORS contract blood-vessels, lessen the 

 flow of blood through the vessels, and hence limit local 

 inflammation, prevent escape of lymph and consequent 

 oedema, and arrest haemorrhage. They may act either by 

 stimulation of the vaso-motor nerves or centres, or by 

 directly stimulating the involuntary muscle in the arteriole 

 walls to contract. They are represented by ergot, lead 

 acetate, and notably adrenalin, full doses of digitalis or 

 strychnine, and other heart tonics, and topical application 

 of cold. Ice or refrigerant lotions applied to circumscribed 

 spots contract the arterioles, and even considerable arteries, 

 and thus relieve congestion, inflammation, and pain. In 

 like manner, ice, when swallowed, arrests bleeding from the 

 stomach, reflexly checks bleeding from the lungs, and, 

 moreover, acts as a cardiac sedative. When the bleeding 

 vessels cannot be reached, either directly or reflexly, ergotin 

 is injected hypodermically. 



MEDICINES ACTING ON THE DIGESTIVE SYSTEM 



ON THE SALIVARY GLANDS. SIALAGOGUES ANTISIALICS 

 REFRIGERANTS. 



ON THE STOMACH. ANTACIDS GASTRIC TONICS 

 STOMACHICS BITTERS EMETICS ANTI-EMETICS GASTRIC 

 SEDATIVES. 



ON THE INTESTINES. PURGATIVES CARMINATIVES INTES- 

 TINAL ASTRINGENTS ANTISEPTICS . 



ON THE LIVER. HEPATIC STIMULANTS CHOLAGOGUES 



HEPATIC DEPRESSANTS. 

 ON THE PANCREAS AND SPLEEN. 

 ON WORMS. ANTHELMINTICS VERMICIDES VERMIFUGES. 



SIALAGOGUES are drugs which increase the secretion of 

 saliva. This alkaline fluid comes from the secreting glan- 

 dular cells, which are replenished with fresh materials from 

 the blood-vessels of the glands. The process of salivation 

 is regulated by a nerve-centre in the medulla, and subsidiary 

 nerve-centres (ganglia) in the several glands. By food or 



