172 VEGETABLE PARASITES. 



In spite of the application of emollients and lotions the head 

 of the patient exhibits a certain inflammable redness, disorders of 

 digestion come on, and a painful feeling of oppression ; a sign 

 that a foreign body has its seat in the follicles of the hair, which 

 sustains the irritation. This rechiess only disappears on bald 

 places and on the scars which succeed the falling off of the hair. 

 The hair becomes altered more and more, loses its colour, 

 becomes atrophied, varying in its diameter in different places, it 

 becomes mouse-gray or ash-coloured, woolly, and falls out. The 

 hairs may be drawn out with their bulb by means of a pair of 

 pincers, or they separate from their root by breaking off at the 

 level of the skin. The bare spots form complete scars, in which 

 the bulb of the hair and the whole pigment are destroyed by the 

 fungus. Sometimes remains of the hair are seen entangled in the 

 epidermis. Baldness commences, as in most diseases of the 

 scalp, in the back and lateral parts of the head ; the back of the 

 head resists longest. The mass of favi may be compared to dried 

 birds 5 dung, and is possessed of a most repulsive smell, similar to 

 putrefying animal matter. During this latter period the favus is 

 apt to spread to other parts of the body, and this spreading is 

 accelerated by the simultaneous Herpes circinnatus, or by the 

 scratching of the patient. The Favus alveolaris is found in every 

 region. 



2. Favus scutiformis, F. nummularis, Porrigo scutulata, Favus in 

 rings, circles, groups, &c. It is primary, or follows chronic 

 eczema, impetigo, or lichen, and exists only in the scalp, and in 

 conjunction with a strong growth of the hair. The alteration of 

 the hair is, during the first period, less perceptible than in the 

 last form. During the second period this species appears at first 

 as a more or less extensive round spot, from half an inch in 

 diameter to that of a five- franc piece. The pericranium appears 

 elevated, swollen, reddish, and painful ; the surrounding regions 

 depressed. Sometimes the hair which covers the spot is sur- 

 rounded at its base with a small epidermal capsule, whitish or 

 yellowish- white, forming a kind of covering to the hair. This 

 excessive formation of epidermis continues a long time, and 

 the favus might then easily be mistaken for pityriasis of the 

 scalp. The form of the affection, the adherence of the scales, 

 the gum-like aspect of the epidermal covering of the hair, the 

 colour of the branny scales, form the distinctive characters of 

 this disease. The cells of the epidermis become smaller and 



