142 VEGETABLE PAEASITES. 



above the edge of the skin together with the hair, the latter 

 breaks off. 



The cylinder of the hair is quite filled with spores, and its 

 substance is entirely indiscernible. The growth of the plant 

 goes on quickly ; but it is inside the substance of the hair. 

 In the scales which cover the head itself the fungus is never 



O 



found. 



Effects of the parasite. Small rugged elevations on round spots 

 are observed, chiefly on the part of the head which is covered 

 with hair, and which give to it the appearance of the seal-skin. 

 The hairs are broken off at 1 2'" above the edge of the 

 epidermis in a regular manner, and baldness is the inevitable 

 result. The skin is dry in such patches, firmer and more con- 

 tracted than on the surrounding parts. Small rough inequalities, 

 similar to those on the skin of a goose, may be observed and 

 felt. The colour of the skin is a little bluish. On scratching, 

 the skin becomes covered with a white dust resembling fine bran. 

 The disease shows itself at first in a very small spot in the middle 

 of the circle which it afterwards forms, and grows from thence 

 eccentrically. The same takes place when the patches are at 

 last uniting into one. Sometimes this disease spreads over the 

 whole hair of the body, and attacks even the nails. 



The nature of the disease is well illustrated by the case observed 

 and communicated by Malmsten : 



A mother observed, in November, 1843, when she was combing 

 the hair of her boy, three years old, a little to the right of the 

 large fontanel, a small hairless spot covered with white scales, 

 which became larger, in spite of carefully combing off the scales. 

 In February, 1844, this spot was lg inch in diameter, and was 

 covered with grayish-white little scales, from which issued and 

 grew up a number of small smooth hairs, 2'" in length, and 

 quite lustreless. The spot was dry, rough, and grayish. On 

 scratching off the scales the skin was found to be not in the least 

 injured, and looked healthy all around. At a short distance a 

 similar bald spot was seen, 2'" in length, from which the whole 

 of the hair had not yet fallen off, although some of it looked as if 

 cracked off. When the hair had been allowed to grow for some 

 time, some became bristling, whilst the rest remained lying 

 smoothly on the head and was easily pulled out. Every hair, 

 however, was bent, at the height of 2"' above the skin, into an 

 angle. On the 1st of July the spot had increased to 2", 



