88 



muscles more energetically, from which it appears that the lethal 

 dose of the a-acid is distinctly higher for cold than for warm-blooded 

 animals. When introduced by way of the stomach, the a- and 

 /3-acids, even when employed in large doses, are alike inoperative ; 

 and it may be concluded that the resinous components of hops may 

 be disregarded, so far as concerns the beer in which they occur, for, 

 as DRESER has shown, they are almost entirely converted into 

 harmless derivatives. 



The foregoing review of the present state of our knowledge 

 relating to the bitter principles of the hop, although somewhat brief, 

 is intended to give the reader a survey of the manifold views and 

 investigations in this domain ; and, in addition, to serve the experi- 

 menter as a guide to the extensive literature, the study of which 

 must, of necessity, precede further researches. Let us hope that 

 such researches, adding to this branch of our knowledge, may soon 

 be undertaken, and prove of benefit, to the brewing industry. 



