FACE-MITES. 



47 



are described next, it has been thought best to discuss them 

 in this place. 



Face-mites live in the sweat-glands at the roots of hairs 

 and in diseased follicles in the skin of the human face, chiefly 

 about the nose, eyes and chin where they cause the well- 

 known comedones or black-heads; they also occur in a num- 

 ber of domesticated animals. Such diseased follicles become 

 filled with a plug of fatty matter the upper end of which is 

 usually hardened and blackened. If these "black-heads" 



are forced out by pressure the 

 minute mites may be found in 

 all stages of development. To 

 detect them more readily it 

 is necessary to dissolve this fatty 

 matter in a drop of oil or ether. 

 The young mites possess six legs, 

 the adults eight; both are quite 

 worm-like in appearance, their 

 elongated abdomen is trans- 

 versely wrinkled; their mouth is 

 a suctorial beak possessing dag- 

 ger-shaped mandibles with two 

 palpi. In the adult parasite the 

 four pairs of legs are very short, 

 two-jointed and each armed with 

 four claws. 



These mites cause no harm 

 to man except marring his 

 or her beauty, but they can se- 

 verely injure dogs, cats, hogs, 

 sheep, horses and cattle; sometimes they even produce upon 

 them a scab-like disease called the "red-mange," and in ex- 

 treme cases they can cause the death of their hosts. Dogs 

 and cats sometimes suffer very much from their presence, 

 and in the case of a dog as many as ten to one hundred and 

 more mites have been found in a single hair-follicle. In bad 

 cases the hair falls out, and the skin becomes covered with a 

 reddish scab, v^hich is very diflficult to eradicate, and almost 

 never without the loss of all the hair: in fact a cureisconsid- 



Fig. 24. Face-inite of man. greatly 

 enlarged. Original. 



