The term is used to denote a morbid condition of the liver increased in size by the excessive accumulation of fat, sufficient to interfere with the healthy action of that organ. Observation has shown that the quantity of fat contained in the livers of dogs is influenced by the diet, and a large quantity may be accounted for by that which is taken in with the food. Fat is however found in the body independently of that which is introduced by the stomach as experimental observation has proved. Oily matters must essentially enter to some extent into the composition of the food, in order to maintain the animal in a good condition.

All flesh and vegetable substances contain more or less fats which are not transported into the body to be deposited there unchanged. On the contrary they are altered and used up in the processes of digestion and nutrition; while the fats which appear in the body are in great part of new formation, produced from materials derived from a variety of sources.

Fatty liver rarely if ever occurs as an independent affection and its importance as relates to disease has never been determined. The presence of fats in an abnormal quantity, in the secreting cells of the liver, might by their presence seriously interfere with circulation, and might in extreme cases be sufficient to obstruct the bile and occasion slight jaundice.

The cause of the disease under consideration is no doubt largely influenced by fatty food, conjoined with insufficient exercise; the method of the accumulation of oily matters in the liver being much the same as in the production of the "foie gras" of geese.

Insufficient material for the study of the disease when it occurs independently of other affections leaves but an imperfect knowledge of the symptoms.

Impaired digestion, vomiting, progressive emaciation, loss of strength, and slight jaundice later in the disease, are the common, evidences of fatty liver. If the organ is much enlarged the fact can be determined, but the increase in some cases is insufficient to be detected, and it is to be remembered that a diminution in size may occur from the accumulation of fat in the secreting cells.

In the treatment abuses are to be corrected, over eating prevented, fatty food excluded from the diet, exercise insisted upon, and tonics should be given if the need is apparent.

That starchy food has certain fattening properties is well known; it is not certain however whether the constituents of the same are directly converted into fat, or are first taken up and distributed in the system, and afterwards supply the materials for its production. When the allowance of saccharine matters is restricted, the decrease in weight is more rapid.