292 HUMAN PHYSIOLOGY CHAP. 



the serum of horses that have been inoculated with the 

 disease germs ; it is called diphtheria antitoxin. 



201. Scarlet Fever. This disease is probably caused 

 by a germ, although as yet scientists have not been 

 able to find out the real -cause. The disease is con- 

 tagious and infectious at all times, but especially in the 

 later stages, when the epidermis begins to peel off in 

 fine particles. These little particles may be carried 

 from one person to another in various ways and by 

 numerous agencies. Scarlet fever at the house of the 

 dairyman has been known to infect the milk and cause 

 the disease. 



A rash or skin eruption occurs on the second day, 

 on the chest and thighs. It soon spreads to all parts 

 of the body. In about ten days the skin begins to peel 

 off, and this may continue from one to five weeks. 

 This is the time of greatest danger, and the patient 

 should be kept isolated from all other persons during 

 the entire time, and be properly cared for, because a 

 cold is sure to affect the kidneys or ears, and may 

 leave these organs permanently weak, or even result 

 in death. 



202. Measles. The cause of measles is unknown, 

 but it is one of the most contagious diseases of child- 

 hood. It usually begins with a cold in the head, and 

 on the fourth day an eruption of the skin appears on 

 the face, which later spreads to all parts of the body. 

 The disease is most contagious in the early stages, 

 before the rash appears, and for that reason precaution 

 cannot be taken in time to prevent its spread. 



