Prolonging the life of the old dog depends directly on our knowledge of the diseases of old age. The study of the diseases of old age is called geriatrics, and it is only in recent years that it has been subjected to systematic and critical consideration. It was not so long ago that the treatment of the diseases of old age consisted essentially in an effort to keep the patient comfortable, the casual administration of drugs that would relieve pain, and the application of halfhearted medical measures, given with a kind of benign hopelessness. The outlook was generally a dismal one. Veterinary medicine had little faith in its ability to combat nature in this regard.
The diseases of old age were accepted as somehow inevitable and research was therefore not sufficiently stimulated to undertake the quest of solving the problems involved. The result was that if a dog did live to a ripe old age, it was due more to extraordinary vigor or to meticulous care than to any exceptional medical efforts on the part of the veterinary surgeon.
The fact is that most dogs did not often get the opportunity to become old. Potent diseases readily decimated their numbers while they were still in the prime of life. There simply were not many old dogs around. Neither the interest nor the opportunity nor the necessity to study the diseases of old dogs seemed apparent. And science usually records its most dramatic achievements when the interest is present, the opportunity to study is available, and the necessity is relatively immediate.
The situation has changed drastically in the last few decades. Remarkable discoveries in the form of life-saving drugs and refinements in surgical techniques have so substantially increased life expectancy that dogs have continued to live into hoary old age in increasingly larger numbers, until they now account for a respectable percentage of our canine population. The mere presence of such overwhelming numbers of old dogs supplied the interest, the opportunity, and the necessity for the systematic study of the diseases of old age. Though geriatrics is still in its infancy, its achievements have already been noteworthy and it continues in ever-widening measure to contribute to our understanding of the diseases of old age, with its consequent prolongation of the life of our favorite pet, the dog. In this regard, veterinary science owes an inestimable debt to human medical research.
There is no hard-and-fast rule by which old age can be strictly defined. Some dogs, like some people, grow old at an earlier age than others. The life span of the average dog ranges from about nine to thirteen years, though cases of dogs living from fifteen to twenty years are not uncommon. We would be safe, then, in classifying as aged dogs those from about eight to ten years old, while being aware of individual differences wherein animals might become old below or above this range.
Old age is specifically characterized by the appearance of gray hair under the lips and around the nose, with gradual extension to the region of the eyes and to the forehead. The ends of the digits become enlarged and the claws have a tendency to become curved and elongated. Often the muzzle also becomes enlarged. In some animals, especially those that are affected with a chronic skin irritation of the back and loins, there may be a partial loss of hair and a general thickening of the skin in the diseased area. The appearance of warts is quite common in many breeds. As a dog gets older, the color of the pupil of the normal eye seems to change gradually from deep blue to whitish. Some dogs have a tendency to increase somewhat in weight, but most often there is a gradual loss of weight and dehydration of the tissues of the body. That there is a gradual though obvious loss of vigor goes almost without saying.