REPORT OF THE BUREAU OF ANIMAL INDUSTRY. 489 

 "LEECHING" OF HORSES AND CATTLE. 



Dr. J. C. Neal, Archer, Fla., writing under date of July 13, 1887, 

 gives the following description and history of a disease known as 

 " Leeching," to which horses and cattle in that locality are subject: 



I send you to-day a specimen of diseased tissue taken from the lower jaw of a 

 horse. This represents a singular disease peculiar, I think, to this section, very 

 common and very fatal to horses and mules. The common name is " Leeching." 



In the central part of this State are hundreds of ponds, usually with a belt of 

 grassy prairie around, and a hummock, rocky, and with hard-wood trees growing 

 densely. Nearly all of these lakes are shallow, with water-grass, water-lilies, etc., 

 growing on the margins. Into these grassy places the horses, mules, and cows that 

 are " turned out " for the summer on the prairie go often, till they can barely keep 

 their feet, and feed all day in the water. After a varying exposure to the influence, 

 or whatever it may be called, of the " pond," a slight lump or elevation of the skin 

 may be found on some part of the body that has been submerged. To the touch it 

 will feel as if a grain of shot were lodged beneath the skin. In eight or ten days 

 the skin sloughs off centrally over this hard spot, and discovers a bloody, bruised- 

 like surface, exuding serum and blood no pus. This rapidly grows in size till in a 

 few weeks there is a raw surface from 4 inches to 1 foot square. This drops blood 

 and serum, but no pus. An examination will show, usually, a mass of yellow, gritty 

 growth, coral-like in shape, imbedded in a mass of bruised, bloody tissue, dark in 

 color and the edges roughened, elevated above the skin, and the skin decaying at 

 the outside of the ulcer. The leech invades any tissue, but seems most common on 

 the legs, abdomen, and sides. Occasionally it is found in the head. The invaded 

 tissues decay slowly, and apparently without pain. I have seen hoofs cut off, the 

 abdomen opened, the eyes eaten out, the teeth destroyed, etc. 



This specimen was from the mouth of a four-year-old gelding, and when first 

 found the animal was walking around with open mouth, tongue out, and dripping 

 blood. At the request of the owner I had the animal thrown and made an exami- 

 nation. I found an ulcer occupying all the lower jaw from the front teeth to the 

 roots of the tongue. This was about 2 inches thick an open, offensive ulcer, with 

 points of the gritty leech protruding, giving it a roughened look and feel. The 

 ulcer extended over the edge of the lower teeth, hindering mastication. There was 

 a small bunch at the angle of the jaw outside the skin not broken, also one in 

 the face near the right eye. I cut to the bone and found the leech imbedded in that, 

 and also in the tongue, and pronounced the case incurable. 



The treatment is to cut off all diseased tissue and scar with hot iron or nitric acid, 

 or nitric acid followed by carbolic acid. Still, if the disease invades the abdomen, 

 the hoof, or the mouth, there is no known remedy. During the last twelve years I 

 have devoted some time to the study of this unique trouble, and can give you some 

 facts regarding it. 



It does not occur in cypress ponds. It happens that in ponds with cypress at one 

 end only, there will be leeching only at the other end. 



All ponds do not leech. Often, of two ponds within half a mile of each other, one 

 only will leech stock. 



All horses do not leech, only those of good blood. The Cuban and Texan ponies 

 as a rule are exempt. 



It is not contagious. A sucking pony may be badly leeched and the dam will 

 lick the ulcer, and yet not be affected. Dogs, chickens, and cats will greedily eat 

 the cut-out fragments of a leech and not take the disease, nor do those who cut out 

 the spot ever have any trouble. 



The mule is rarely affected, cows still more rarely. 



The period of incubation is from one to eight days. One attack does not protect 

 against another. Some horses leech every year. 



Upon examination of the specimens forwarded by Dr. Neal the 

 sections showed considerable cell infiltration, which was probably 

 due to inflammatory changes. There were also a few centers which 

 seemed to be in a condition of necrosis, as they failed to stain. Ow- 

 ing to the manner in which the specimens had been taken out it was 

 difficult to identify what particular tissues the pieces represented. 

 In some the mucous membrane showed quite distinctly, as did also 

 a salivary gland. The examination failed to reveal the nature of the 

 disease. 



