This brings us sharply to the fact that the most important factor in the cure of diphtheria, just as in the case of tuberculosis, is early recognition. How can this be secured? Here again the bacteriologist comes to our relief, and we needed his aid badly. The symptoms of a mild case of diphtheria for the first two, or even three, days are very much like those of an ordinary sore throat. As a rule, even the well-known membrane does not appear in sufficient amounts to be recognizable by the naked eye until the middle of the second, or sometimes even of the third, day. By any ordinary means, then, of diagnosis, we would often be in doubt as to whether a case were diphtheria or not, until it was both well advanced and had had time to infect other members of the family. With the help of the laboratory, however, we have a prompt, positive, and simple method of deciding at the very earliest stage. We merely take a sterilized swab of cotton on the end of a wire, rub it gently over the surface of the throat and tonsils, restore it to its glass tube, smearing it over the surface of some solidified blood-serum placed at the bottom of the tube, close the tube and send it to the nearest laboratory. The culture is put into an incubator at body heat, the germs sown upon the surface of the blood-serum grow and multiply, and in twelve hours a positive diagnosis can be made by examining this growth with a microscope. Often, just smearing the mucus swabbed out of the throat over the surface of a glass slide, staining this smear, and putting it under a microscope, will enable us to decide within an hour. These tubes are now provided by all progressive city boards of health, and can be had free of charge at depots scattered all over the city, for use in any doubtful case, within half an hour. Twelve hours later a free report can be had from the public laboratory. If every case of suspicious sore throat in a child were promptly swabbed out, and a smear from the swab examined at a laboratory, it would not be long before diphtheria would be practically exterminated, as smallpox has been by vaccination, and this is what we are working toward and looking forward to.