ITCH 345 



spread with renewed vigor with the coming of warm weather. 

 So persistent is the infection that it is doubtful whether it ever 

 spontaneously dies out. "Norwegian itch," caused by Sarcoptes 

 scabiei crustoscE, is even more persistent than ordinary itch, and, 

 unlike the latter, may occur on the face and scalp as well as on 

 other parts of the body. 



Infection can result only from the passage of male and female 

 mites, or of an impregnated female, from an infected to a healthy 

 individual. Normally this takes place by actual contact, rarely 

 in the daytime on account of the secretive habits of the mites, 

 but commonly at night, especially from one bedfellow to another. 

 Gerlach experimented to determine how long the mites could 

 live away from their hosts and found that in the dry warm air of 

 a room they lost vitality so rapidly that they could not be re- 

 vived after three or four days. In moist places, on the other 

 hand, such as in the folds of soiled underwear or bedcloths, they 

 survived as long as ten days. From this it is evident that in- 

 fection may take place by means of bedding, towels, underwear 

 or other cloth which may come in contact with infected skin. 

 The author once witnessed an epidemic of itch arising from the 

 use of an infected wrestling mat in a college gymnasium. It is 

 also possible for infection to be derived from mangy animals, 

 though the mites, once adapted for several generations to a 

 given host, do not survive a transfer to a different species of host 

 more than a few days. 



Treatment and Prevention. — The treatment of itch before 

 the nature of the malady was understood was considered very 

 slow and difficult, and even at the present time it is looked upon 

 by many people as a disease which can be recovered from only 

 after prolonged treatment. The fact that the mites burrow 

 beneath the skin to lay their eggs makes careless superficial 

 treatment almost as inefficient as the internal medicine which 

 was once taken to " purify the blood." The most effective 

 treatment for the itch is as follows: the patient rubs himself 

 vigorously with green soap and warm water for about 20 minutes, 

 and follows this with a warm bath for half an hour or more, dur- 

 ing which the soapy massage continues. In this manner the 

 skin is softened, the pores opened and the burrows of the mites 

 soaked so that the application of mite poison which is to follow 

 will penetrate more readily. When the skin is thus prepared 



