was your control? How many cases did you have under identical conditions, and how many of them did not get the treatment?" Now Martin began to mouth it—control, control, control, where's your control? where's your control?—till most of his fellows and a few of his instructors desired to lynch him.
He was particularly tedious in materia medica.
The professor of materia medica, Dr. Lloyd Davidson, would have been an illustrious shopkeeper. He was very popular. From him a future physician could learn that most important of all things: the proper drugs to give a patient, particularly when you cannot discover what is the matter with him. His classes listened with zeal, and memorized the sacred hundred and fifty favorite prescriptions. (He was proud that this was fifty more than his predecessor had required.)
But Martin was rebellious. He inquired, and publicly, "Dr. Davidson, how do they know ichthyol is good for erysipelas? Isn't it just rotten fossil fish—isn't it like the mummy-dust and puppy-ear stuff they used to give in the olden days?"
"How do they know? Why, my critical young friend, because thousands of physicians have used it for years and found their patients getting better, and that's how they know!"
"But honest, Doctor, wouldn't the patients maybe have gotten better anyway? Wasn't it maybe a post hoc, propter hoc? Have they ever experimented on a whole slew of patients together, with controls?"
"Probably not—and until some genius like yourself, Arrowsmith, can herd together a few hundred people with exactly identical cases of erysipelas, it probably never will be tried! Meanwhile I trust that you other gentlemen, who perhaps lack Mr. Arrowsmith's profound scientific attainments and the power to use such handy technical terms as 'control,' will, merely on my feeble advice, continue to use ichthyol!"
But Martin insisted, "Please, Dr. Davidson, what's the use of getting all these prescriptions by heart, anyway? We'll forget most of 'em, and besides, we can always look 'em up in the book."
Davidson pressed his lips together, then:
"Arrowsmith, with a man of your age I hate to answer you as I would a three-year-old boy, but apparently I must. Therefore, you will learn the properties of drugs and the contents of prescriptions because I tell you to! If I did not hesitate to waste the time of the other members of this class, I would try
