428 APPLIED PHYSIOLOGY 



pestilence from which few persons escaped, and had 

 almost exterminated the native tribes of some parts of 

 America ; but since that time it has been largely controlled 

 owing to the wide use of a method of conferring immunity 

 to the disease. 



Smallpox begins as a painful fever, and in about four days the skin 

 breaks out with raised spots which become filled with a creamy pus, and 

 leave deep scars at the end of the disease. The disease sometimes 

 occurs in a mild form which is mistaken for chicken pox, and yet those 

 who take it from these mild cases may have it in its most severe form. 



Smallpox usually spreads directly from the sick to those who come 

 near them. Clothing and other things which the sick have handled 

 may also be the means of spreading the disease even months after the 

 sick are well, for the germs are long-lived if they are kept from the air 

 and sunlight. Every case of smallpox should be closely quarantined, 

 and nothing should be taken from the sick room unless the germs on it 

 are destroyed. 



Vaccine. 



On bone points, inclosed in glass cases. In liquid form, in a small sealed tube. 



746. Vaccination. There is a mild disease among cows 

 called cowpox or vaccinia, in which the skin breaks out as 

 in a mild smallpox in man. If a bit of the matter from one 

 of the sores is rubbed upon a scratch on a person's arm 

 the germs produce a sore spot on the skin, and at the same 



