494 GENERAL DISEASES. 



TRANSMISSION OF THE DISEASE.— Ulcerative lymphangitis 

 is probably coram unioated by contagion only from one animal (.0 

 another. Nocard considers that it is not very readily transmitted 

 and that consequently it is not a particularly dangerous disease. 



TREATMENT. — Antiseptic treatment applied to the ulcers or to 

 the interior of the abscesses after they have been opened, is often 

 followed by rapid healing, which may produce only a temporary 

 good result, for the disease is liable to re-appear at any time in 

 other places. 



Weed (^Lymphangitis). 



This is a condition of the system characterised by inflammation 

 of the lymphatic glands of one, or more, of the limbs. 



The usual CAUSES are over-feeding on nutritious food ; a 

 change of food — especially one of " green meat " — given in a 

 huge quantity ; and neglect of regular exercise. Errors of food 

 and want of exercise are, generally, oo^mbined in the production 

 of this disease. Wounds of the feet sometimes give rise to a 

 foi'm of this complaint. 



NATURE OF THE DISEASE.— Besides the arteries, capillaries and 

 veins, which are essentially concerned in the conveyance of blood, there is 

 another system of vessels called the lymphatics, the function of which is to 

 take up nutritive material from the intestinal canal, and, also, to remove 

 waste products from the tissues. The lymphatics somewhat resemble the 

 veins ; as they are, at first, very minute, and, then, gradually enlarge. In 

 health, the superficial lymphatic vessels are not outwardly apparent to the 

 eye ; but, when irritated, they become swollen and painful. In the hind 

 leg, which is the usual seat of this disease, they follow the course of the 

 great saphena vein which runs, up the inside of the hock and thigh. 

 Exercise quickens the circulation of the fluid (lymph) which flows through 

 the lymphatics ; but want of work naturally tends to retard it. When 

 lymph stagnates — if I may use the term — in the lymphatics, especially, if 

 the horse, for some tiine previously, has been fed on highly nutritious food, 

 it is apt to cause irritation in the glands, through which it passes. It is 

 not improbable that, owing to its retention in these vessels, the lymph 

 undergoes some unhealthy change. When an animal has been fed on highly 

 nitrogenous food, the waste products of the tissues will be much more 

 unstable in their cornposition than they would be were the percentage of 

 nitrogen less. Again, we are aware that the circulation of both blood and 

 lymph in the limbs of the horse — especially in the hind extremities — is 

 peculiarly dependent on exercise. Hence, the probable reason for lymph- 

 angitis appearing in the extremities ; for its selecting the hind limbs in 

 preference to the fore ones ; and for its being induced by idleness and high 

 feeding. Why it should occasionally occur, as it is said to do, while an 

 animal is in a starving condition, though doing no work at the time, is 

 somewhat difficult of explanation. Perhaps the lymph, when no food has 

 been given for some time, becomes abnormally rich in nitrogen. I can offer 

 no explanation as to the preference exhibited by this disease, according to 

 good authorities, for the near hind leg, rather than for the off one. 



