I never worked for a private practitioner while I was a veterinary student. Summer vacations were spent working on Colorado ranches where I had ample opportunity to practice much of the theory I had learned in school. But at the ranches I never once had contact with a veterinarian. Western stockmen, then as now, did most of their own doctoring. Consequently, I really had little practical experience when I graduated. This was especially true of small-animal medicine.

One of the peculiarities of medical training is that the students cannot understand which of the myriad diseases they study are commonplace and which are exotic. Cushing's disease is awarded far more lecture time than allergic dermatitis or tonsillitis, although the former is rare and the latter two are everyday diseases. Nothing illustrates this fact more vividly than my first two patients in private practice.

At the Arizona state board examinations, I had been approached by a local small-animal practitioner, Dr. Sol Shapera, who had a small clinic attached to his home and practiced alone. He asked if I wanted to serve a two-week relief hitch while he and his wife took a long-awaited vacation. I eagerly accepted, thereby launching myself on a one-year career as a relief practitioner in Arizona. So as soon as I had passed my boards, I reported to the Shapera home. Before I could get out of the car, Dr. Shapera and his wife popped out of the front door, suitcase in hand. I was handed the house key and given the name of a nearby pharmacy from which to order needed supplies and the name of another veterinarian for consultation purposes.

"Don't worry," said Dr. Shapera as he drove away. "You'll make a few mistakes, but you'll be OK."

I moved into their home, inspected the adjoining clinic, had dinner, and then retired early. At 10:30 p.m. the bedside telephone rang. I bolted upright, heart pounding. My initiation into private practice had begun!

The female caller anxiously described incomprehensible signs in a Chihuahua. Now wide-awake, I suggested she bring in the patient. Dressing hurriedly, I put on my crisp new white smock, carefully placing my stethoscope in one pocket where it could be readily seen. Half an hour later I was examining an obese Chihuahua bitch, trying desperately to understand why, although her temperature was normal, she would not eat, hid under her bed, growled at her two spinster owners, acted worried and neurotic, whimpered incessantly, and kept licking an old sock.

"Does she have rabies?" asked one of the anxious owners.

For all I knew, the dog did have rabies. I examined and muttered and sweated and listened through the stethoscope for minutes at a time, stalling for an inspiration. Periodically I walked with feigned calmness into the backroom where I frantically flipped through the Merck Veterinary Manual, agonizing over what to do next. Wiping away the sweat on my brow, I would fix what I hoped was a relaxed and confident smile on my face but which probably more resembled a tetanic grin and reenter the examination room with a penlight or some other piece of useless equipment.

It was well past midnight. I had been futilely examining the little dog for over an hour. Finally, while I was palpating the dog's belly for the 10th time, one of the owners chirped, "Oh, look! She has milk in her breasts. Some just squirted out."

At last, I knew the diagnosis: false pregnancy! I would later be able to make this diagnosis in a minute, even by telephone. "Well," I said, with an air of patient arrogance. "I think you'd probably like to know why Chiquita is behaving so oddly."

The next morning my first case was a litter of 3-day-old golden retrievers. All of them had large symmetric swellings under their throats. "Did you just move from the Great Lakes?" I asked the owner.

"How did you know that?" the owner asked, amazed.

"Because this is congenital goiter," I explained. "It occurs only in certain iodine-deficient areas of the United States."