16 



HISTORY, BOTANY, ECONOMIC USES, 



the oil which remains adhering to the resin. The same 

 treatment is recommended several times, and continued until 

 the resin has lost all trace of bitterness. 



The etherized oil of hops is a yellow oil, obtained, it is 

 said, in the proportion of 2 per cent, from hop dust by 

 distillation. I have, however, never seen it obtained in 

 such a quantity. The resin retains moreover a very large 

 quantity of oil. This volatile oil is more or less soluble in 

 water, it easily dissolves in alcohol and in ether. Its specific 

 weight has been found = 908. 



Way and Ogston on the one hand, and Hawkhurst on the 

 other, have determined by analysis the constituent inorganic 

 parts of hops. Watts and Nesbit have also effected the 

 determination of them. 



The following are their respective analyses : 



It is chiefly to its bitter principle that the physiological 

 action which hops exert is generally due ; this action has 



