70 HYPNOTICS 



sleep, certain parts remaining in a state of partial unregu- 

 lated activity, induce the phenomena of dreams, which occur 

 in the domesticated animals as well as in man. 



A perfect hypnotic has not yet been found even for 

 human patients. Those prescribed are liable to be un- 

 certain, and injuriously disturb motor, organic and trophic 

 functions. Hypnotics act still less satisfactorily on the 

 lower animals, on account of the want of development of the 

 cerebrum. Dogs and pigs are, however, brought under 

 their influence more readily than horses or ruminants. 

 The agents most trusted are opium and morphine, chloral 

 hydrate, croton chloral, hyoscine, cannabis indica, and 

 bromides. Opium and morphine prove of special value, not 

 only in depressing cerebral functional activity, but also in 

 antagonising pain and irritation which interfere with sleep ; 

 but not to an equal extent in all animals, for in the cat, 

 and to a less extent in the horse, excitement and restlessness 

 are caused. Bromides diminish conduction of impressions, 

 and hence notably quiet cerebral excitement. Chloral is a 

 powerful hypnotic, but in large doses it is a local irritant, 

 and sometimes also produces dangerous delirium and con- 

 vulsions. It induces sleep mainly by its depressant action 

 on the brain, and by dilating vessels generally. Chloral- 

 amide is prescribed for human patients as a safe and effectual 

 hypnotic. Paraldehyde, even in full doses, has none of the 

 disadvantageous secondary effects of opium or chloral, 

 causes quiet sleep in dogs, but is rather nauseous, and not 

 one- third of the strength of chloral. Sulphonal is more 

 active, but being insoluble, hypnosis is slowly established. 

 It has been used especially in cases of motor unrest. Large 

 doses diminish excitability of the reflex functions of the 

 spinal cord, and also of peripheral sensations. Trional is 

 allied to sulphonal, but is more soluble and active ; and in 

 experiments on dogs it produced sleep more rapidly. Hyp- 

 none, urethane, and amylene hydrate, though ineffective in 

 the horse, are useful hypnotics for the dog. Warmth to the 

 body and legs, and comforting warm drinks withdraw blood 

 from the brain, and hence favour the anaemia which occurs 

 in sleep. 



NARCOTICS are drugs which disturb the relation of the 



