HYDROCYANIC ACID. 25 



water ; soluble in alcohol ; slightly so in ether ; unites with acids to 

 form salts. Brucia is found in false Afigustura bark; its properties 

 are similar to those of strychnia, though feebler. 



Effects on System, — Given in very small doses it acts as a tonic 

 to the digestive organs ; in rather larger quantities, its influence 

 seems to be directed chiefly to the muscular system, through the 

 medium, however, of the spinal marrow. There is, at the same 

 time, an increased sensibility to external impressions, trembling of 

 the limbs, and slight convulsive motions, which subsequently extend 

 to the involuntary muscles, producing, in poisonous doses, the most 

 violent tetanic spasms ; the individual perishes apparently from 

 asphyxia, brought on by the spasm of the respiratory muscles. 

 There is no narcotism, nor is the pulse much affected. 



There is strong reason for believing that the peculiar impression 

 of the medicine is exerted entirely through the medium of the spinal 

 marrow, and not through the medium of the brain. 



Uses. — The cases which would seem most obviously to be met by 

 nux vomica, or strychnia, are those attended with deficient nervous 

 energy, as indicated by a torpid or paralytic condition of the muscles. 

 The cases of paralysis to which it is applicable are such as are not 

 attended with organic lesion of the brain. It is said to be more ad- 

 vantageous in paraplegia than in hemipliegia ; also in local palsies, 

 and in incontinence of urine, depending on a loss of power of the 

 muscles of the bladder. The first obvious sign of its influence on 

 the system, in cases of paralysis, is a tingling sensation experienced 

 in the part affected. 



Dose of the powder — 5 grs. three or four times a day, gradually 

 increased until a sensible effect is produced. A better form is the 

 alcoholic extract, the dose of which is from half a grain to two grains. 



Dose of strychnia — ^\th to |th of a grain, three times a day. 



Strychnia may be applied endermically in cases of amaurosis, 

 when not of an organic character, — half a grain being sprinkled upon 

 a blistered surface on the temple. 



Hydrocyanic Acid. — (Acidum Hydrocyanicum, U. S.) 



This acid is a compound of hydrogen and cyanogen, and is of 

 vegetable origin, being found in the bitter almond, cherry laurel, and 

 in most of the species of the prunus and amygdalece. Usually ob- 

 tained, however, by decomposing the bicyanide of mercury, by hy- 

 drochloric, or hydrosulphuric acid. The concentrated, or purest acid 

 is a limpid fluid of a sp. gr. of 0*697 ; having a strong peculiar 

 odour, which, however, difl^ers from that of the oil of bitter almonds, 

 extremely volatile ; boils at 79° ; has a great tendency to undergo 

 decomposition, and is extremely poisonous. It is never employed in 

 the undiluted form. 



The medicinal or dilute hydrocyanic acid is procured by the re- 



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