Previous to making a brief reference to this diseased state, it is necessary to tell the reader a few points of importance in connection with the healthy heart of the dog. It is a hollow, muscular organ, with a right and left compartment (the ventricles). In shape it is like a cone, th apex of the cone pointing downwards and backwards. The base is made up of two compartments of the body. These large vessels serve to suspend the heart in the chest cavity, says Frank Townsend Barton in British Fancier.

"The blood coming from these vessels first of all passes into the two compartments at the base (auricles), and from these through valves into the compartments first mentioned, and called the ventricles.

"The weight of the heart varies according to breed and age, but it has been estimated that it runs from 3 to 7 per cent of the weight of the animal. It is enclosed in a bag .pericardium). When perfectly healthy it should be dark red in color, firm to the touch of the finger, and the traces of fat running down the various grooves upon its surface are a sign of a well-nourished organ.

"Now, when it is affected by what is called fatty degeneration, it becomes very pale, thin and flabby, greasy to the touch, with one or more patches of fat upon the walls of the ventricles. This is brought about by the muscle fibres composing the heart being changed or replaced by fat.

"In order to bring about this condition the dog need not be fat itself; in fact, a heart in this state is far more likely to be found in a dog which is thin or underfed.

"Dogs which are excessively fat externaly generally show the same internally; that is to say, that the heart, kidneys, liver, etc., may be completely imbedded in one mass of fat; but then it must be understood that this is not a diseased state and does not interfere with the animal's health so long as it allows these different organs to perform their work. It is a sign of over rather than one of under nutrition.

"The fatty degenerated heart is a diseased one. This is not technical. It is called an 'infiltration,' a term which means that fat is formed between the muscular fibres.

"I am not aware that there is any symptom or symptoms during life which will enable us to tell whether the heart is in this diseased state. An opinion can only be purely speculative. Of course, the heart has a weak beat, and the animal is easily knocked out. Sudden death is likely to occur either from failure of the heart's action, or, if the fat is in the form of a patch upon the wall, from sudden rupture of the wall at this spot, whereby the blood would gush suddenly out of the heart into the bag containing it. ceasing to beat at once.

"The animal must be prevented from any severe exertion. "It has been stated that this disease is common among pampered, asthmatical pets, the truth of which is open to serious doubt."

This is perhaps the most frequent form of heart disease found in the dog; it is, however, seldom diagnosed during life. A postmortem will show in such cases that the fibres of the muscles are dotted with small dark, spots (these are globules of oil within the sheath of the fibre), the heart tissue is soft and breaks down readily under the finger. Cause may arise from a general malnutrition of the system, or from senile decay due to old age. The organ not always wholly involved, and when only a part is affected it is due to some obstruction, causing local malnutrition.