Page:Popular Science Monthly Volume 45.djvu/555

Rh become accurate observers of disease. This knowledge can only be obtained by diligent work in your dissecting rooms and laboratories; there is no royal road to it. Do not forget that you are all disciples of William Harvey, John Hunter, and Charles Darwin.

To sum up in one short sentence. Your observations will consist in comparing your ideal standard of the normal with any conditions you consider to be aberrations from that type. Then, having made your observations, the next thing you have to learn is to arrange them in their proper proportional perspective and to rightly interpret their true significance. Given certain altered conditions, how have they been produced? What have been their antecedents? Prof. Huxley has called the interpretation of these facts "retrospective prophecy." In his book called Science and Culture there is an interesting address entitled After the Method of Zadig: Retrospective Prophecy as a Function of Science; and as this method is one which you as students will largely adopt I will venture to read to you the story of Zadig. It is very doubtful where this philosopher lived. Babylon claims him; but he appears to have forsaken this city to live on the banks of the Euphrates, where he could be alone with Nature to investigate and unravel her mysteries.

The story is briefly this: The chief eunuch having been sent in search of the queen's dog, which had been lost, met Zadig, who had seen the markings on the sand left by the straying animal, and from this was able to give almost an exact description of its appearance. Later on the grand huntsman came the same way looking for one of the king's horses which had been lost, and Zadig, having noticed the marks on the sand and the disturbances among some trees through which the animal had passed, was able in like manner to describe it. As neither of the animals could be found, Zadig was accused of having stolen them; he was taken prisoner and brought before the court, and sentenced to transportation. No sooner was the sentence passed than the missing animals were found, so the judges had to reverse their sentence, but fined him four hundred ounces of gold for saying he had seen that which he had not seen. After paying the fine he explained to the court how he had been able so exactly to describe the animals; from this his fame spread widely. The king commanded that the gold should be returned to him; this was done, but three hundred and ninety-eight ounces were retained by the court for legal expenses, etc.

You will be saying. But, after all, this method is only applied common sense; but let me tell you that it is a very great advance on certain other methods which have been adopted by the so-called wise men through the ages. It is not so long ago that