Tinea Tonsurans. Circinate Ringworm. 19 



of endothrix. In Cincinnati Hospital, in one year, Ravogli found 

 five cases in children, all endothrix and derived from other child- 

 ren, and nine cases in adults, all edothrix and attributed to animals. 

 Probably the two forms are varieties, determined by habit, and 

 the transition takes place most readily by transference from ani- 

 mals to man. 



Accessory Causes. These are the same as favor the crypto- 

 gams in general : Youth, confinement in close, damp, dark, winter 

 quarters; moulting ; abrasions by wounds, rubbing, vermin, etc.; 

 accumulation of cutaneous secretions or exudates ; crowding 

 together of affected and healthy animals ; the common or succes- 

 sive use of blankets, covers, buildings, cars, boats, rubbing posts, 

 head ropes, halters, harness, etc., and the neglect of the free use 

 of rubber, brush or currycomb. Above all the neglect to sepa- 

 rate healthy stock from affected animals and men, and the places 

 they have occupied. It is conveyed in sucking, in copulation or 

 indeed by any direct contact, and the spores are readily carried in 

 dry dust to fresh .subjects. Judging from prevalence the order of 

 susceptibility may be thus stated : man, ox, dog, horse, goat, cat, 

 sheep and pig. Rabbits can be readily inoculated, and mice, rats 

 and small rodents often convey the disease to the larger animals 

 and man. 



Symptoms and Lesions. Certain lesions are common to the 

 different forms of the disease in the various animals. On delicate 

 skin, comparatively destitute of hair, as the lips, eyelids and inner 

 side of the ear, the first indication may be a red papule, which 

 gradually extends outward day by day, so as to form a more or 

 less circular spot. The surface becomes scaly, the scales rising 

 as a whitish concretion, and the hairs standing erect, splitting up 

 into filaments, breaking across and finally dropping off so as to 

 leave an absolutely bald centre. If wetted with chloroform a 

 number of hairs near the bare .spot become bleached, yellowish or 

 gray, while the more distant and healthy hairs are unaffected. 

 Other spots tend to appear in the near vicinity, where the spores 

 have been lodged and thus a series of round, bare, scurfy spots 

 are formed, which encrease from within outward, after the man- 

 ner of fairy rings that grow mushrooms or toadstools on old 

 pastures. The scurf may disappear from the centre while Still 

 extending at the periphery, as if the tissues had become immune. 



