542 APPLIED BIOLOGY 



the alcoholic liquors whose physiological effects are under 

 consideration. We shall see that the effect of alcoholic 

 liquors is largely in proportion to the amount of contained 

 alcohol, and so it is justifiable and convenient to deal directly 

 with the effects of alcohol and neglect, temporarily, the minor 

 fact that alcohol, as commonly taken in wine, beer, whisky, 

 etc., is diluted with water and variously flavored. 



467. Is Alcohol a Poison ? In popular usage, the word 

 " poison " is associated with such powerful substances as 

 arsenic, strychnine, snake-venom, and others which, when 

 introduced into the human body, produce marked and even 

 fatal disturbances. In scientific usage the term is applied 

 to many substances which cause demonstrable disturbance of 

 any function of the body. There is no substance which is 

 always a poison, for even strychnine and ricin may be diluted 

 so as to produce no noticeable disturbance. A cup of coffee 

 is not poisonous to an average adult, and yet it contains a 

 greatly diluted dose of caffein, which in large amounts is a 

 poison. Tea, coffee, ginger, pepper, and many other things 

 taken with food contain small quantities of substances which 

 in large amounts are poisons. Even common salt in very 

 large quantities has proved a fatal poison. Evidently the 

 word " poison " has a relative significance, and involves the 

 quantity. In general, we apply it only to substances which 

 in very limited quantity are harmful. The question, then, 

 " Is alcohol a poison? " can be answered only by reference 

 to the amount of alcohol and to the constitution of the indi- 

 vidual who drinks it. That alcohol in large and intoxicating 

 doses has proved fatally poisonous is well known, and that 

 it commonly produces profound disturbances of various 

 organs when used excessively and habitually is also common 

 knowledge ; but whether alcohol in very small quantities is 

 a poison, is a difficult scientific question which only physi- 

 ologists can answer by experimental studies made with ani- 

 mals and men. 



