10. Cerebral Excitants, Stimulants, Antispasmodics (L. stimulare, stimulus, to urge, stimulate, a goad, excitant; Gr.
a spasm). - These increase the functional activity of the brain without causing subsequent depression or suspension of the cerebral functions: valerian, asafetida, sumbul, musk, camphor, guarana, caffeine (theine), alcohol.
11. Cerebral Depressants, Sedatives (L. sedare, sedatus, to allay, calm, a pacifier, tranquillizer). - These lower or suspend the higher brain functions after a preliminary stage of excitement: (a) Narcotics (Gr.
numbness, stupor) - which at first excite and stimulate all the body functions, then cause profound sleep, stupor, coma, insensibility, and death by paralyzing the medulla-centres governing respiration and other vital functions: opium, morphine, cannabis, lactucarium, cimicifuga; (b) Hypnotics, Soporifics, Somnificants (Gr.
L. sopor, heavy sleep, somnus, sleep, + facere, to make) - which produce sleep, leaving undisturbed the normal relationship of the mental faculties to the external world; in a broad sense these include narcotics and anaesthetics: hydrated chloral, sulphonal, trional, paraldehyde, chloralformamide, urethane, potassium, sodium, and ammonium bromides; (c) Anodynes, Analgesics (Gr.
pain, without pain, cures pain) - which relieve pain by either depressing sensory centres or impairing nerve-fibre conductility: opium, morphine, belladonna, hyoscyamus, stramonium, coca, cocaine, hops, antipyrine, acetanilid, phenacetin; (d) Anaesthetics (Gr.
sensible, insensible effect produced) - which reduce sensory nerve-functions until nerves cannot receive or conduct sensation; some directly depress the skin's end-organs, others impair the sensory nerve con-ductility, others reduce local circulation; these are mostly volatile substances, whose vapor when inhaled sufficiently causes complete unconsciousness, loss of sensation and motion; anodynes only diminish, while anaesthetics temporarily destroy skin and mucous membrane sensibility: ether, chloroform, nitrous oxide, ethyl bromide, methylene bichloride.
Motor Excitants (Excito-Motors, Spinants). These increase functional activity of the motor apparatus and spinal cord, causing, in large doses, disturbances of motility, increased reflex excitability, and tetanic convulsions, finally paralysis from over-stimulation: nux vomica, strychnine, ignatia, picrotoxin, electricity.
Motor Depressants (Depresso-Motors). These lower functional activity of the motor apparatus and spinal cord, in large doses directly paralyzing them: physostigma, conium, gelsemium, potassium, sodium, ammonium, and lithium bromides, amyl nitrite, nitroglycerin, lobelia, alcohol, ether, chloroform.
14. Mydriatics (Gr.
enlarged pupil). - These dilate the pupil; some act locally, other systemically, causing paralysis of the ciliary muscle: atropine, homatropine, hyoscyamine, daturine, duboi-sine, cocaine. 15. Myotics (Gr.
to close, shut). - These contract the pupil by stimulating the circular muscular fibres of the iris, and by contracting the ciliary muscle so that the eye is accommodated only for near objects: physostigmine, pilocarpine, morphine, anaesthetics (at first), muscarine.