GENERAL THERAPEUTICS OF THE GLANDS 129 



daily by horses at work is 10 to 20 liters; this amount can be in- 

 creased three-fold with arecoHne or pilocarpine. The salivary 

 glands (parotid, submaxillary, sublingual, glands of the cheeks, 

 lips and gums) are connected with nerve centres in the medulla 

 oblongata and brain. Their peripheral secretory nerves are the 

 facial, sympathetic and glossopharyngeal; vasomotor and motor 

 nerves are also present. The secretion of saliva is increased directly 

 by the stimulation of the salivary centres and nerves (arecoline, 

 pilocarpine) and reflexly by the ingestion of food, by mechanical, 

 chemical, thermic and electrical stimulation of the mucous mem- 

 brane of the mouth and stomach; also by stimulation of the splanch- 

 nic nerves. The constituents of saliva, in addition to water 

 (98 to 99.5 per cent.), are ptyalin, albumin, mucin and salts (so- 

 dium chloride, sodium carbonate, phosphates, sulphates, potas- 

 sium sulphocyanide). The normal salivary secretion of the 

 horse amounts to 10 to 40 liters; by artificial stimulation with are- 

 coline and pilocarpine this quantity can be obtained in a few hours 

 (laminitis). 



1. DRUGS THAT STIMULATE THE SECRETION OF SWEAT 

 DIAPHORETICS 

 Synonyms: Hidrotics, sudorifics, diapnoics. 



Actions. — The drugs which stimulate the secretion of sweat 

 cause an increased evaporation (diapnoics) or an increase in the 

 amount of visible, watery sweat secreted by stimulation of either 

 the peripheral nerves of the sweat glands, the sweat centres in the 

 medulla or the secretory cells of the glands; by depression of the 

 inhibitory nerves, or by dilation and relaxation of the cutaneous 

 vessels and consequent hyperaemia of the skin. Those which 

 operate upon the nerves or cells of the sweat glands (hidrotics) 

 may be designated as direct diaphoretics. To this group belong 

 arecoline, pilocarpine and ammonium acetate. Indirect dia- 

 phoretics, which first produce hyperaemia of the skin and then 

 increased diaphoresis (sudorifics), include warm water internally 

 and moist heat externally. Finally, sweating is also stimulated 

 reflexly by emetics. 



