1 64 Veterinary Medicine. 



trum. Symbiotic Mange is easily distinguished by its location 

 on the digits, by its indisposition to extend, by its being less con- 

 tagious, and by the bilobed abdomen in the male parasite. 

 Phthiriasis is easily distinguished by discovery in the affected 

 parts of the hsematopinus tenuirostris, the enlarged abdomen 

 of the parasites standing out at right angles from the skin. 



Prognosis. Sarcoptic Scabies is a purely local disease caused 

 and maintained by the acari in the skin. The burrowing habits 

 of the acari, however, and the difficulty of reaching all by acari- 

 cides, together with the extreme and constant irritation, the loss 

 of rest, the exhaustion, the unfitness for work, tend to render the 

 disease extremely intractable and inveterate, and to lead to 

 debility, anaemia and even death. The affection is dangerous in 

 all, but preeminently so in the old, or very young, the weak, 

 overworked, underfed, filthy, ungroomed animals kept in close 

 foul stables. Army horses, in campaign work, are dangerous 

 subjects. The more recent and circumscribed the affection the 

 better the hope of a speedy and complete recovery under energetic 

 treatment . 



Lesions. In addition to the morbid phenomena seen in life, 

 the burrows and galleries may be shown in a fragment of infect- 

 ed skin, which has been kept in moist warmth for 24 to 48 hours 

 and the loosened epidermis removed by forceps and scalpel. In 

 a bright light a magnifying lens shows the channels straight or 

 winding, 2 to 4 mm. long, with at intervals enlargements or gal- 

 leries, each containing two or three eggs or egg shells, and in the 

 terminal one the ovigerous female. A general yellow infiltration 

 under the skin may be so abundant over the galleries as to form 

 a ve-sicle, and in other cases it dries up so as to cause hard, thick 

 epidermic crusts and scales. The implication of the hair follicles 

 causes depilation, and the dermatitis leads to subcutaneous en- 

 gorgement, especially noticeable in the limbs (Delafond and 

 Bourguignon). 



Treatment. On the first indication of mange the horse must 

 be separated from all others, also all his belongings, clothes, 

 brushes, combs, rubbers, scrapers, harness, pole and shafts. The 

 disease must be accurately diagnosed by the discovery of the sar- 

 coptes. 



Clipping of the entire animal is essential to reveal every isolated 

 and unsuspected point of attack and to facilitate the application 



