SOME TROUBLESOME INVADERS 



349 



The whole series of investigations by Webster and his 

 associates and by the physicians Schamberg and Gold- 

 berger afford a most interesting illustration of the often- 

 times intimate interrelationships of animals and plants 

 and the incidental effect upon man. 



Nature of the injury. — The presence of the mites on 

 the human skin causes a severe eruption or dermatitis. 

 The eruption is liable to cover 

 the neck, chest, back, arms, 

 and legs. It consists of wheals 

 or inflamed spots from the 

 size of a pea to that of the 

 finger nail. In severe cases 

 there may be thousands of 

 these wheals on the body. 

 The spots are round, oval, or 

 irregular in shape, and of a 

 rose color. 



Itching is one of the first 

 symptoms of the trouble and 

 is especially intense at night. 

 In some cases the temperature 

 rises, while in other cases 

 headache, nausea, and a mild 

 form of diarrhea may develop. 

 Occasionally patients complain of pains in the joints 

 and in the back. Ordinarily the itching subsides in 12 

 to 36 hours, although it may continue for weeks if the 

 mattress is continually used. 



Life history and habits of the mite. — The adult female 

 mites are so small as to be almost invisible to the naked 

 eye. The body is elongated and furnished with four pairs 



Fig. 119. — The female mite, 

 much enlarged. 



