54:2 AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



Hydrocyanic Acid, HON. — This is likewise a strong poison. Amygdalin is a glucoside 

 occurring in cherry-pits, in bitter almonds, etc., together with a ferment ealled emulsin, 

 which hitter hasthe power of transforming amygdalin intodexfcrose, benzaldehyde, and hydro- 

 cyanic acid. Bydrocyanic acid, therefore, gives its taste to oil of bitter almonds, and it 

 may likewise be detected ill cherry brandy. 



Potassium Cyanide, KCN. — This and all other soluble cyanides arc fatal poisons. 



Acetonitril, or Methyl Cyanide, CH S CN. — This and its higher homologous nitrils 

 are violent poisons. After feeding acetonitril in small doses, formic acid (see p. 534) and 

 thiocyanic acid (see below) appear in the urine, the thiocyanic acid being a synthetic prod- 

 uct of the ingested cyanogen radical, and the HS — group of decomposing proteid. 1 After 

 feeding higher homologues of acetonitril or hydrocyanic acid, thiocyanide likewise appears 

 in the urine. Since the amount of thiocyanide in the urine is normally very small, there 

 is no reason for believing that cyanogen radicals similar to those described above are ever, 

 to any great extent, cleavage-products of proteid. 8 Through intravenous injections of 

 sodium sulphide, and especially of sodium thiosulphate, poisonous cyanogen compounds 

 may be administered much beyond the dose ordinarily fatal: 8 



NaCN + S0 2 < |^ a a + = NCSNa + Na 2 S0 4 . 



Cyanamide, NC.NH 2 . — This is a laboratory decomposition-product of creatin, but does 

 not occur in the body. It is poisonous when administered. When boiled with dilute 

 sulphuric or nitric acids it is converted into urea : 



NCNH, + H 2 = H 2 NCOXH 2 . 

 It is to be remembered that creatin in the body is not converted into urea. 



Ammonium Cyanate, OCN(NH 4 ). — Boiling ammonium cyanate converts it into 

 urea. This was shown by Wohler in 1828, and was the first authoritative laboratory 

 production of a body characteristic of living organisms: 



OCNiNH 4 )=OC(NH 2 ) 2 . 

 This reaction illustrates Pfliiger's idea of the transformation of the unstable cyanogen radical 

 in living proteid into the amido- compound in the dead substance. According to Hoppe- 

 Seyler, the urea-formation in the body is as indicated in the above reaction, but that no 

 cyanic acid or ammonium cyanate is to be detected on account of their extreme instability. 



Potassium Thiocyanide, NCSK. — This substance is usually found in human saliva to 

 the extent of about iU>] per cent., and in the urine. Since it contains nitrogen and sul- 

 phur its original source must be from proteid. The amount in the urine is probably wholly 

 and quantitatively derived from that in the saliva. 4 If thiocyanides be fed, they appear 

 quickly in the urine without change. Thiocyanides are less poisonous than the simple 

 cyanides (see discussion under Acetonitril above). Thiocyanides give a red color with 

 ferric chloride in acid solution. 



Diatomic Alcohol Radicals. 

 Thus far onlv derivatives of monatomic radicals have been discussed ; next 

 in order follow diatomic alcohol radicals, represented by the formula C„H 2I1 , and 

 including the bodies ethylene, H 2 C — CH 2 , propylene, CH 3 — HC = CH 2 , etc. 

 This set of hydrocarbons is called the olefines. The first series of compounds 

 which are of physiological interest are the amines of the olefines. 



Amines of the Olefines. 

 These include the group of ptomames — basic substances which are formed 

 from proteid through bacterial putrefaction. Those which are poisonous are 



1 Lang: Arrhiv fur exper. Pathologic wad Pharmakologie, 1894, P>d. 34, S. 247. 



2 Op. cit., S. 256. 



■ Lang: Archiv fur exper. Pathologic und Pharmakologie, 1895, Bd. 36, S. 75. 

 *Gscheidlen: Pfliigei's Archiv, 1S77, Bd. 14, 8. 411. 



