18 MANUAL OF POISONOUS PLANTS 



although Remak was the first to demonstrate its pathogenic character 

 by direct inoculation. It consists of mycelium and spores, existing in such 

 profusion that it is readily detected. Skin abrasions are an important accessory 

 cause. 



Symptoms. The disease is characterized by dry scabs, brownish or 

 yellowish, gray or silver white on the surface, and white or sulphur 

 yellow in their deep layer. These scabs have a circular form, with a 

 diameter not to exceed that of a dime, and a thickness varying up to one-fifth 

 of an inch. They occasion atrophy of the hair and a slight depression of the 

 skin. These scabs are usually found on the forehead, cheeks, ears, face, abdo- 

 men, external side of the hind legs and in the neighborhood of the claws. At 

 first the scabs are perforated by hairs which soon fall out. Later the skin 

 exfoliates under the scab and leaves a pit. In the horse the scabs may become 

 confluent and form bands as wide as the finger. Itching is observed in the 

 dog. In most cases the progress of the disease is quite rapid although the 

 prognosis is favorable unless the disease has become too far advanced. 



Lesions. According to Robinson the parasite first obtains a lodgment 

 in the funnel-shaped depression in the epidermis, through which the hair 

 shaft emerges upon the surface. It grows luxuriantly in the upper part 

 of the hair-sac and insinuates itself on all sides between the superficial 

 layers of the epidermis. When it reaches a short distance on all sides of the 

 hair follicle it breaks up the looser layers and appears on the surface producing 

 the characteristic cup-shaped bodies. It also invades the hair shaft itself, pene- 

 trates between the cellular layers of the root sheath and by its mechanical pres- 

 sure upon the papillae interferes with the nutrition of the hair and causes it 

 to fall out. If the pressure is sufficient to cause atrophy of the papilla, a new 

 growth does not occur. 



In the skin the parasite usually confines itself to the upper corneous cells 

 and does not extend to the living tissues. In cases where the surface is covered 

 by irregular confluent masses of the parasites, the entire upper layer of the 

 epidermis will be found infiltrated with the achorion. 



The corium itself is usually in a state of chronic inflammation, and 

 suppuration, which may be quite abundant, often occurs under crusts. Even in 

 the absence of pus, the pressure of the parasite causes atrophy of the skin, and 

 at last pit-like depressions or more extensive reddened scars are left. The 

 disease ends with the destruction of the glandular structures of the skin. 



Treatment. This is purely local except when debiKty complicates the 

 disease, in which instance tonics should be administered to build up the 

 system. As for the local treatment, its aim is to destroy the para- 

 site and relieve the cutaneous irritation. The dry scabs may be softened and 

 removed by thoroughly washing with soft soap and water. The removal of the 

 hairs, by extraction, from the affected part has been attended with good success 

 since, in so doing, many of the parasites are disposed of. A liniment composed 

 of liquid tar and green soap two parts and alcohol one part will prove beneficial 

 since it is antiparasiticide, disinfectant, dessicating, emollient and cleansing. 



Mercuric chlorid in one to two per cent aqueous solution tincture of iodine, 

 sulphur iodid ointment, red iodid of mercury ointment 1-8, sulfur ointment, etc., 

 are all useful applications. It is advisable to clip the hair from unaffected parts 

 adjacent to the diseased foci, so that any spread of the malady may be immediate- 

 ly detected. Whatever the treatment, it is a good plan to wash daily with soft 



