ACARUS DEM OBEX FOLLICULORUM 471 



in the same animal. The pustular form is the most common, and may 

 be recognized by the hair falling out, by hypenemic and swollen skin, 

 which becomes thickened and in folds, and red from lack of pigment, 

 forming nodules often the size of a millet seed, which change from 

 bluish-red to yellow pustules, and finally the purulent bloody contents 

 escape, and in it and under the membrane we find hundreds of acari. 



The itching, as a rule, is never very great, as in sarcoptic mange, 

 and in some cases not even present. When the affected cutaneous 

 regions are scratched or rubbed, the patients, as a rule, resent it and do 

 not derive the pleasure that scratching gives in sarcoptic mange. The 

 disease spreads very slowly, the eruption starting at the head and between 

 the toes, and in only very rare instances does it cover the whole body 

 (see Plate). The parts that are affected finally heal, l)ut the skin 

 remains thick, denuded of hair, marked in some places by scars or cica- 

 trices, and also by cracks and wrinkles. In some cases we may have a 

 dark pigmentation marked with warty projections. When there is any 

 itching present the appearance of the cutis may be changed materially 

 by secondary eczema. The appetite is very rarely afTected, the animal 

 eating well, although some cases, in spite of good food, have shown the 

 animal to have an impoverished, unhealthy look. 



The squamous form is seen in the neighborhood of the eyes, the 

 In-idge of the nose, forehead and the anterior surface of the neck (Fig. 171) 

 and breast, but it may show itself in other parts of the body. It is a 

 normal cutaneous inflammation accompanied by falling out of the hair 

 and great accumulation of scabs, and isolated bare spots resembling 

 alopecia areata. The hair drops from the afTected places. The skin is 

 only slightly reddened, but covered with thick scabs. If these places 

 are squeezed, the parasites can be pushed out of the skin very rapidly. 

 The easiest way to obtain the parasites is to rub the blunt end of a knife, 

 previously clipped in oil, over the affected parts, and the microscope will 

 aid you in distinguishing this disease from simple scaly eczema. In any 

 suspicious bald spots on an animal, it is always well to scrape off a portion 

 of the affected part and give it a close examination under the microscope. 

 The pustular form seems to be more frequently observed in the last few 

 years. This form of the disease appears as a series of hard nodules in the 

 skin, ranging in size from a millet seed to that of a pea, and when they 

 appear in numbers they are apt to become confluent and merge into one 

 nodular mass, and the tissue in the affected region assumes a reddish- 

 blue color. On pressure of one of these nodular masses there exudes 

 from it a purulent sanguineous fluid which, when examined under the 

 microscope, is found to contain numerous dermodectic acari. After the 

 nodules empty or are evacuated, the skin becomes covered with scales 

 or crusts. The animal is not itchy in this condition, or if so it is in very 



