These terms are employed to describe a condition we cannot with any certainty determine during life. It is one of abiding inflammatory irritation of the connective tissue which unites the ducts and secreting lobules of the gland wherein changes of structure occur of a gradually progressive and permanent character. It is more frequently met with than the acute form of inflammatory action already alluded to. At first the liver is increased in volume, as the result of an abiding congestion of its vessels and an excessive growth of connective tissue, which later on undergoes contraction, resulting in wasting and destruction of the gland. As the organ shrinks it becomes hard or cirrhotic, and in this condition its function is greatly impaired.
It is mostly found in aged horses, after a long spell of luxurious living and indolence combined. It is also seen in association with the presence of parasites, especially the Echinococcus veterinarum. But there are many cases which cannot be referred to either of these causes, and for which no special reason can be assigned.
These are mainly concerned with the digestive function, which for some time before the disease has been suspected will have exhibited indications of increasing impairment. The insufficient and irregular supply of bile furnished by the gland is accountable for the varying state of the bowels, which at one time are constipated, at another unduly relaxed, and now and again the seat of pain, as manifested by symptoms of colic. The mucous membranes, as those of the eyes, nose, and mouth, may or may not present yellow discoloration as a constant condition, but where this is not the case observations made from time to time will sooner or later detect more or less bile-staining, not only of the mucous membranes but also of the urine. Evidence of a disordered digestion is further shown by clamminess of the mouth, and sour breath, flatulency, and thirst. In addition, the patient is dull, unthrifty in appearance, and soon exhausted under work. Lameness of the right fore limb may also be present. In extreme cases dropsy of the belly results from the impediment which the disease has put to the circulation of the liver.
Treatment in the majority of established cases is not very hopeful, but as the extent of the disorganization can never be accurately measured in the living animal, and comparative health may be enjoyed by horses in whom a limited portion of the liver has ceased to be of any functional value, we should not condemn a case as hopeless until some remedial measures have been tried. A course of saline medicine, preferably sulphate of magnesia, followed by nitrohydrochloric acid and vegetable tonics, should precede a long holiday in a good pasture. By these means there is reason to suppose that the disease is sometimes arrested in its progress, and a period of usefulness may ensue. The symptom of dropsy in the young is not so formidable as in the stabled animal that has seen service, and with a suitable dietary, medicaments may in such cases prove serviceable in restoring the function of the liver and exciting absorption of the fluid which distends the abdomen. Fresh tops of the broom (Scoparii cacumina) have the reputation of carrying away abdominal ascites, and failing the plant we may use the decoction prepared according to the British Pharmacopoeia. Tonics, by improving the general health, will afford assistance in relieving the local ailment and of preventing further escape of fluid into the belly. Absorbent and diuretic remedies undoubtedly carry away existing accumulations, and should not be overlooked. Here iodide of potassium and nitrate of potash may be employed either separately or together. Tapping the abdomen and removing the fluid bodily is sometimes resorted to, but it is seldom of much use beyond affording temporary relief, unless the liver trouble can at the same time be relieved.