ON ACCURACY IN OBSERVATION. 537 



become accurate observers of disease. This knowledge can only 

 be obtained by diligent work in your dissecting rooms and labo- 

 ratories ; 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 con- 

 sist 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 Sci- 

 ence; 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 transpor- 

 tation. No sooner was the sentence passed than the missing ani- 

 mals 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 ani- 

 mals ; 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 



