OP THE HUMAN SKIN. 17 



parel, a constant field of food. But though the 

 skin is mostly affected at these parts, any portion 

 of it which is covered may show signs of the ver- 

 min, since the patient will not only scratch where 

 the insect bites, but any part of the cutaneous 

 surface ; it being a well-known fact, that to allay 

 the sensation of itching it is not necessary to 

 scratch exactly where the source of irritation 

 exists. 



Since the insect lives in the recesses of the 

 clothes, and sallies forth from there to prey upon 

 the skin for existence, a person so affected is quite 

 free of vermin when naked, a few adhering to the 

 skin, whilst the clothing removed may be a living 

 mass of them. It is the constant wearing of the 

 ■same clothing, therefore, which affords a perma- 

 nent home for these insects. According to the 

 numbers present, and the cutaneous sensibility of 

 the individual infested, will be the amount of irri- 

 tation produced, and the consequent amount of 

 scratching. At first the slight itching occasions 

 only streaks of white or red from the marks of the 

 finger-nails, but afterwards excoriations are seen 

 from the further injury of the skin. These exco- 

 riations will have little drops of dried blood, the 

 2 



