Diagnosis. Prognosis. 9]^5 



For tbe i^urpose of mieroscopic examination cue scrapes away with a scalpel 

 the epidermis scales or scabs from the most recent lesions, or from the deeper 

 layers of the crusts, and carefully draws out the hair at the margin of the spots, 

 especially hairs surrounded by gray sheaths (fungous mantle). Sometimes the ex- 

 cision of a small piece of skin may become necessary, because it may not be possible 

 to find fungi in the crusts and hairs (Troster). The material, which may previously 

 be defatted by immersion in absolute alcohol, ether or chloroform, is placed into 

 1% potassium hydrate solution for a few hours to V2 to 1 day, according to the 

 thickness of the crusts, and small particles of the scales or crusts and fragments 

 of hairs are examined under 400 to 500 magnification. One may also adopt Sabou- 

 raud 's procedure of placing only the roots of the hairs on a slide, then adding potas- 

 sium hydrate and, after putting on a cover glass, warming over a flame until the solu- 

 tion of potash boils, if the hairs are very thick. Besides fungous elements which are 

 arranged in the way already related (see page 900, Fig. 130) one also finds split hairs. 



A macroscopic reaction of hairs attacked by fungi was announced by Dyce 

 Duckworth and by Behrend, which consists in treating the fungus-containing hairs 

 with chloroform and evaporating, when the hairs appear chalky white, while after 

 moistening with oil their color returns. The reaction is due to the fact that air 

 vesicles collect in the hairs which have become split and teased out by the fungi; 

 after the extraction of the fat the air vesicles reflect the light and in this way 

 cause a whitish color of the hair. By subsequent moistening with oil the original 

 condition is restored. 



Favus of sucking animals is sufficiently distinguished from 

 ringworm by the characteristic scutula ; the hairs are not split 

 up and brittle in favus, consequently no hair stumps are to be 

 seen on the skin, and after treatment with chloroform no white 

 color appears. In alopecia areata the skin appears healthy, 

 scale formation is absent, and no hair stumps project from the 

 skin. In seborrheic eczema the sharp borders of the spots and 

 the brittleness of the hairs which fall out as a whole are absent. 

 The maculous form of acariasis sometimes causes the whole 

 hair to fall out, but in the fluid contents pressed out from the 

 skin the hair sac mites may be found. Sarcoptic scab is distin- 

 guished from ringworm on account of its localization and the 

 appearance of local changes, and besides by the mode of exten- 

 sion and the severe itching. 



Prognosis. Ringworm of domestic animals is a benign dis- 

 ease in so far as a cure may generally be brought about in 2 to 

 3 months by appropriate and continued treatment. Spontaneous 

 healing is not uncommon, especially if the eruption is not very 

 extensive. One notices this chiefly in cattle and in adult animals 

 if they are removed from damp stables and are kept in the open 

 in dry, sunny weather. In herds ringworm disappears spon- 

 taneously in a short time if the stable is warm and if the herd 

 is small, so that the contagion is rapidly transmitted through 

 the entire stable; otherwise the atf'ection is apt to become 

 stationary. In this connection the character of the disease is not 

 without influence, since in certain years the disease occurs in a 

 particularly malignant form. In young animals (sucking calves 

 and lambs) ringworm is usually very obstinate and causes nutri- 

 tional disturbances, which may, however, also be noted in older 

 cattle; exceptionally the disease may also cause death. The 

 more extensive the eruption, the more difficult is its cure. 

 In consequence of repeated recurrences and relapses the disease 



