POISONS AND POISONING. 



By V. T. Atkinson, V. S. 



[Revised in 1904 by Leonard Pearson, B. S., V. M. D.] 

 DEFINITION OF A POISON. 



To clearly define the meaning of the word ' ' poison " would be some- 

 what difficult. Even in law the word has never been defined, and 

 when a definition is attempted we are apt to include either too much 

 or too little. The following is perhaps as satisfactory a definition 

 as may be given : A poison is a chemical substance having an inher- 

 ent deleterious property rendering it capable in small quantities of 

 producing serious functional disturbances upon gaining access to 

 the system by the usual channels ; or it is a substance which, when 

 introduced into the system or applied externally, injures health or 

 destroys life irrespective of mechanical means or thermal changes. 

 The common conception of a poison is any substance which, in 

 small quantity, will destroy life, excepting such as act by purely 

 mechanical means, as, for example, powdered glass. 



Some substances that are not usually looked upon as poisons may 

 destroy life if given in large doses, such as common salt. Other sub- 

 stances which are perfectly harmless when taken into the body in the 

 usual way are poisons if injected into the circulation, such as distilled 

 water, milk, or glycerine. Living organisms are not "chemical sub- 

 stances," and are not considered in this connection. 



SOURCES OF POISONING. 



Poisoning may come from many causes, among the chief of which 

 are the following: 



(1) Errors in medication. — By using the wrong substance or too 

 large dose an animal may be poisoned. 



(2) The exposure of poisons used for horticultural, technical, or 

 other legitimate purposes.— Poisons used for spraying plants, disin- 

 fecting, poisoning vermin, dipping sheep, painting, smelting, dyeing, 

 or other purposes, may be so handled as to come within the reach of 

 animals. 



(3) Damaged food.— Food that has undergone putrefaction or cer- 

 tain kinds of fermentation or heating, or food that is infested with 



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