16. C ROT A LI D.^ 



The severity o£ the symptoms which follow a snake 

 bite vary with the nature of the poison, the amount of the 

 poison, the size of the person or animal bitten, and the rapid- 

 ity with which the poison enters the circulating blood. 



The nature of the poison varies with the kind of snake. 

 In western North America, however, Coral Snakes are small 

 and quite rare and occur only in Sonora, Arizona and south- 

 ern Utah. Practically, our only dangerous snakes are the 

 rattlesnakes. 



The amount of poison thrown into the wound depends 

 on a number of factors. Among these are the size of the 

 snake, its activity at the time, its condition of health and 

 nourishment, the condition of its fangs and whether both 

 cause wounds, the extent to which the snake has depleted its 

 supply of venom by recent use of its poison apparatus, and 

 the protection afforded by clothing, hair, or the resistance 

 of the part bitten. 



With any given quantity of venom thrown into the wound 

 the relative size of the dose depends, of course, on the 

 weight of the victim. Therefore, the danger is greatest 

 when small children are bitten. 



The rapidity with which the poison enters the circulating 

 blood is perhaps the most important factor of all. If it so 

 happened that the fang entered a vein and the venom was 

 thrown directly into the blood, dangerous or fatal effects 

 would follow almost immediately. Fortunately, this almost 

 never occurs. Usually the venom is injected into the sub- 

 cutaneous tissues, and whether its entrance into the blood is 

 rapid or slow depends largely upon whether the bitten part 

 is richly or poorly supplied with blood vessels. Ordinarily 

 some minutes elapse before the onset of symptoms. 



The pain and swelling which follow the bite of a rattle- 

 snake often are very great, and later a blackish or purplish 

 discoloration of the skin about the wound appears, as a re- 



