It is already plain to the reader that the analyst's task is not an easy one. Sometimes the analytical examination is of vast extent; sometimes it is greatly narrowed by hints from the family doctor. These hints are interesting, and show that the doctor is, when he knows his business, a real and a very skilful detective.
The doctor's eye is a wonderful one. When he enters a room, he not only measures the patient from head to toe, notes the colour of his face, the posture of his body, the signs of pain, stupor, or perhaps sham; but observes the manner of the other people present, and sees every bottle, glass, and cup in the place.
Now, although sudden death is usually from natural causes, when it occurs soon after food there is always suspicion, as we have said. So, if the doctor perceives great pain and nausea, he thinks of arsenic, antimony, tinned meats, mushrooms, toadstools, and other things; if the pupil of the eye is as small as a pin-head, and the sick man is drowsy, he thinks of opium; if something seems to have caught hold of the patient's heart, and to be squeezing it like a sponge, he thinks of digitalis; if the poor victim is being worked like a puppet, and his pupils are large with fear, he thinks of strychnine; if there is great thirst, colic, and cramps in the legs, he thinks of lead.
IS IT ARSENIC, OR NOT?
He knows that prussic acid kills like a bullet in the brain—a glass of cold water taken while hot from exercise may do the same—and he smells for it. He can also tell if it is phosphorus or carbolic acid, by the smell.
He knows that relatives usually kill each other by means of particular poisons; that other poisons are used for suicidal purposes; that the photographer takes cyanide of potassium, the medical man and chemist prussic acid or morphia, the poor man vermin-killer or oxalic acid, or carbolic acid, or some such agonising destroyer of life. And thus, though all poisons lead to the same end—stoppage of the breathing and blood circulation—yet each has its own particular way of sending the soul to eternity. He can therefore often tell the analyst detective how to take a short cut.
THE SPECTROSCOPE—AN INSTRUMENT THAT HAS BEEN FATAL TO MANY CRIMINALS.
By the way, there is no such thing as a slow poison—that is, a poison which, taken to-day, does not show its effects for weeks. This is a fiction of the novelists. On the other hand, there is—except in the case of prussic acid and nicotine—no death straight away after taking poison, as one sees it on the stage, Shakespeare notwithstanding.