OF THE HUMAN SKIN. 11 



into the skin of the head to allay the itching, will 

 finally cause inflammation of the cutaneous surface. 

 An artificial eczema, as dermatologists call it, is 

 produced, and this all the more in those persons, 

 children for instance, who are predisposed to 

 eczematous eruptions. This inflammation causes 

 a fluid to exude from the skin, which, with the 

 blood coming from where the cuticle has been 

 deeply torn by the nails, dries up and forms crusts 

 and scales, mixed also with the natural fatty secre- 

 •tion of the scalp, from the sebaceous follicles. 

 Hence the loathsome appearance which such a head 

 presents. Moreover, the greater the amount of 

 exuded fluid, the greater amount of food for these 

 vermin, and the more rapid their growth and mul- 

 tiplication. Thus we see that the irritation of the 

 lice caused itching; this led to the scratching, 

 which, continued for a length of time, produced an 

 artificial eczema, or inflammation of the skin. The 

 exuded fluid of eczema is food for the pediculi, 

 under the crusts and scales the animals can hide ; 

 the matted hair afibrds better opportunity for the 

 eggs or nits to hatch, and so a person who has 

 eczema of the head offers a much better field for 

 the cultivation and propagation of these vermin. 



