PARASITES AND PARASITIC DISEASES OF DOGS 6 



time will allow the real condition to go unrecognized until it is too 

 late to save the animal. Treatment also involves the use of highly 

 potent drugs, carefully selected with due regard to the end to be 

 accomplished, and administered in such doses and in such a way as to 

 cure disease without injuring the patient. The possible contraindica- 

 tions for treatment, conditions which make it evident that certain 

 drugs or doses are dangerous, must be ascertained and kept in mind. 

 The anthelmintics (drugs used to remove worms) are always poison- 

 ous, being intended to poison the worms, and must be given in such 

 doses as will accomplish that object without materially injuring the 

 patient. Insecticides injudiciously applied to the skin to kill parasites 

 may injure the skin or kill the patient. In this discussion of parasites 

 a number of treatments are described, since it may be necessary for an 

 owner to treat his dogs or cats, when the services of a competent 

 veterinarian are not available. It is understood, of course, that an 

 owner gives such treatment at his own risk and that he assumes the 

 responsibility for his diagnosis, selection of drugs, dosage, method of 

 administration and technic, and the risk of possible bad results. 

 Each animal presents his own special individual case, and no general 

 directions can cover all of the possibilities. Passing judgment on the 

 individual case is precisely where the skilled veterinarian becomes 

 indispensable, and whenever possible he should be employed. 



EXTERNAL PARASITES AND PARASITIC SKIN DISEASES 



MANGE 



The dog suffers from mange of three sorts — sarcoptic mange, ear 

 mange, and demodectic mange, whereas cats usually are affected only 

 by the sarcoptic type. Sarcoptic mange in dogs occurs over the body 

 and is characterized by the formation of crusts or scabs in advanced 

 stages of the disease; this form of mange in cats is usually restricted to 

 the head and neck. Ear mange, as the name implies, occurs in the 

 ears. Demodectic mange, also called red mange or follicular mange, 

 occurs over the body and is characterized by a falling out of the hair 

 and frequently a reddening of the skin in the early stages, the condi- 

 tion commonly progressing to the formation of pustules. In this 

 disease and in sarcoptic mange there is a characteristic unpleasant 

 " mousy" odor. 



CANINE SARCOPTIC MANGE 



Cause. — Canine sarcoptic mange is due to the canine sarcoptic 

 mange mite, Sarcoptes scabiei canis, a form related to the spiders. 

 This mite is very small, the largest specimen being less than one- 

 fiftieth inch long. The general appearance under the microscope is 

 that shown in figure 1. The sarcoptic mites, this form and its near 

 relatives, have very short hind legs, not projecting beyond the margin 

 of the body. When a dog is suspected of having mange, a portion of 

 the diseased skin should be scraped with a dull knife and the scraping 

 examined for mites. The scraping must be deep enough to draw 

 blood, as these mites burrow deep into the skin, and it may be neces- 

 sary to make scrapings from several areas. The scrapings should be 

 softened by soaking in a solution of caustic soda or caustic potash for 

 half an hour or more, the strong solutions acting more rapidly than 

 weak ones, and then placed on a glass slide under a cover glass and 



