508 DISEASES OF THE SKIN. 



they are completely softened. The head is then to be enveloped in a 

 poultice for some time, after which it is to be carefully washed several 

 times a day, with soap and water applied on a soft brush. For the 

 removal of the diseased hairs, the method formerly in vogue, of cover- 

 ing the head in a so-called " pitch-cap," and, when the hairs had become 

 firmly adherent, of forcibly tearing it off again, is both cruel and un- 

 certain. It is far better to draw them out one by one with a pair of 

 cilia-forceps. After the first few days, this process ceases to seem 

 tedious and troublesome, and, after a few sessions, a quarter of an hour 

 daily devoted to the purpose will be all that is required. Besides the 

 criterion afforded by then* dryness, their lack of lustre and faded color, 

 the diseased hairs may be distinguished from the sound ones by the 

 fact that they may be extracted with greater ease and with less pain 

 than the latter. This daily brushing and depilation must be steadily 

 continued for several months, if we expect to cure the favus radically. 

 Tedious and troublesome as this treatment is, yet it is the only one 

 from which we can anticipate any benefit. Other remedies are useless, 

 unless applied in combination with the above procedure ; and if so 

 combined, it always is questionable which of the two has really been 

 of service. Even the famous cures of favus, of the brothers Mahon in 

 Paris, which consisted in the inunction of a salve of carbonate of soda 

 with lime, and in afterward powdering the head with charcoal, seem 

 to have been effected mainly by careful depilation. The pariciticide 

 remedies most to be depended upon, during and after depilation, are 

 weak solutions of corrosive sublimate (gr. ij-iv to a pint of water or 

 of alcohol), the oil of turpentine, and very dilute creasote. 



CHAPTER XX. 



HERPES TONDENS. 



ETIOLOGY. Not only herpes tondens, but most cases of herpes cir~ 

 cinatus, as well as many of lichen circumscriptus, impetigo figurata, 

 pityriasis rubra circumscripta, and porrigo asbestina^ depend upon 

 the development of a fungus, the trychophyton tonsurans, which 

 breeds between the epidermic cells, converting them into a white dust, 

 and penetrates into the hairs and hair-bulbs, the latter becoming more 

 or less inflamed thereby. In most cases it may be determined posi- 

 tively, by careful search, that this parasitic disease is transmitted by 

 contagion, and that this transmission takes place less often between 

 man and man, than between man and beast, especially the transfer of 

 the parasite from horses and cows, which are quite often afflicted by it, 

 to men who are brought into contact with them. 



