258 LETTERS TO BROTHER JOHN. 



thorax (chest), and found the heart acting with 

 moderate force and frequency," (now, mark what 

 follows !) " circulating dark-coloured blood. The 

 same phenomena resulted from the injection of 

 two drops of the essential oil of bitter-almonds " 

 (the active principle of which is prussic acid), 

 " diffused in half an ounce of water, into the 

 bowels of a cat."* 



Here, then, we have direct and irrefragable 

 proof that ardent spirit is not only a poison, but a 

 poison of the very same nature as prussic acid 

 producing the same effects killing by the same 

 means, viz. by paralyzing the muscles of respira- 

 tion, and so preventing the necessary change of the 

 black blood into vermilion blood; about which 

 black and vermilion blood I have said so much, in 

 my early Letters. 



The strength (that is, the intoxicating power) of 

 wine and ale depends upon the ardent spirit which 

 they contain. 



A great deal of mischief has arisen from the mis- 

 application of the term " strength" to the intoxi- 

 cating power of " strong drinks," as they are called. 

 Potions are said to be "strong"; and thence, I 

 have no doubt, first arose the silly notion that 



* Paris" a Fharmacologia, Vol. I. p. 244. Sixth Edition. 



