482 MATER i A MEDIC A AND THERAPEUTICS. 



favour the movements of the respiratory air, viz. Belladonna, 

 Stramonium, Hyoscyamus, Lobelia, and Tobacco ; Opium, 

 Chloral, and Cannabis Indica ; Chloroform, Ether, Amyl- 

 nitrite, and Iodide of Ethyl ; Conium, and warm moist air. 



5. Impressions reaching the respiratory centre through other 

 channels than the vagus afford us a remarkably ready means of 

 affecting it. Impressions may be stimulating, including irrita- 

 tion of the fifth cranial nerve in the nose by Ammonia, or on 

 the brow by cold ; of the olfactory nerve by odoriferous sub- 

 stances ; of the optic and acoustic nerves by powerful light and 

 sounds respectively ; and of the nerves of the skin generally by 

 painful impressions, such as nicking with towels, flagellation 01 

 slapping, extreme heat, mustard plasters, and other powerful 

 local irritants. Or we may use measures with a sedative influ- 

 ence on the respiratory centre, including gentle warmth to the 

 surface of the chest in the form of poultices and fomentations, 

 warm baths, and local anaesthetics or anodynes, such as plasters 

 and liniments of Opium, Belladonna, and Volatile Oils (Turpen- 

 tine, Camphor, etc.) applied to the chest- walls. 



6. The Respiratory Centre. Besides those influencing the 

 afferent impressions, a vaiiety of direct stimulants and depres- 

 sants of this centre are in our possession. The force of the 

 nervous discharges may be increased by Ammonia., Strychnia, 

 Belladonna, Stramonium, and Hyoscyamus; probably by Ipe- 

 cacuanha and Antimony temporarily ; and by Alcohol, Ether, 

 and Chloroform, for a brief period at the commencement of 

 their action. On the other hand, the last-named drugs quickly 

 diminish the force of the respiratory centre (Ether less rapidly 

 than the others) ; and the same effect may be produced by means 

 of Chloral, Opium, Aconite, Veratria, Conium, and Physostigma. 



7. The Tracts of the efferent impulses from the respiratory centre, 

 the Spinal Centres of the respiratory muscles, and the Nervo- 

 muscular Apparatus of the chest and larynx may be stimulated, 

 not only reflexly, but directly, by Strychnia, which greatly 

 increases the vigour of the spinal centres ; by electricity applied 

 to the nerve trunks (phrenics, intercostals), or to the muscles 

 directly ; and by all measures which improve the nutrition of 

 the nervo-muscular tissues, such as well-ordered exercise. 

 Conversely, these parts may be depressed by 1 .uysostigma, which 

 greatly diminishes the vigour of the spinal centres ; by Conium, 

 which paralyses the motor nerves ; and by Opium, which de- 

 presses the whole efferent mechanism. The use of these depress- 

 ing measures is almost confined to the muscles of the larynx. 

 Most powerful of all is the method of arresting, or at least con- 

 trolling, the movements of the chest, by direct restraint, which 

 is best accomplished by means of strapping or bandaging. 



