386 POISONS, CONTAGIONS, MIASMS 



introduced into a watery solution of synaptas (a constituent of 

 sweet almonds), it disappears completely without the disengage- 

 ment of any gas, and the water is found to contain free hydro- 

 cyanic acid, hydruret of benzule (oil of bitter almonds), a pecu- 

 liar acid and sugar, all substances of which merely the elements 

 existed in the amygdalin. The same decomposition is effected 

 when bitter almonds, which contain the same white matter as the 

 sweet, are rubbed into a powder and moistened with water. 

 Hence it happens that bitter almonds, pounded and digested in 

 alcohol, do not yield oil of bitter almonds containing hydrocyanic 

 acid, by distillation with water ; for the substance which occa- 

 sions the formation of those volatile substances, is dissolved by 

 alcohol without change, and is therefore extracted from the 

 pounded almonds. Pounded bitter almonds do not contain 

 amygdalin, after having been moistened with water, for that sub- 

 stance is completely decomposed when they are thus treated. 



Volatile compounds cannot be detected by their smell in the 

 seeds of the Sinapis alba and S. nigra. A fixed oil of a mild 

 taste is obtained from them by pressurp. hut no trace of a volatile 

 substance. If, however, the seeds are rubbed to a fine powder, 

 and subjected to distillation with wafer, a volatile oil of a very 

 pungent taste and smell passes ovei along with the steam. But 

 if, on the contrary, the seeds are treated with alcohol previously 

 to their distillation with water, the residue does not yield a vola- 

 tile oil. The alcohol contains a crystalline body called sinapin, 

 and several other bodies. These do not possess the characteristic 

 pungency of the oil, but it is by the contact of them with water, 

 and with the albuminous constituents of the seeds, that the vola- 

 tile oil is formed. 



Thus bodies which would be regarded as absolutely indifferent 

 in inorganic chemistry, on account of their possessing no promi- 

 nent chemical characters, when placed in contact with one 

 another, are mutually decomposed. Their constituents arrange 

 themselves in a peculiar manner, so as to form new combina- 

 tions ; a complex atom dividing into two or more atoms of les3 

 complex constitution, in consequence of a mere disturbance in 

 the attraction of their elements. 



The white constituents of the almonds and mustard, which 



