The Mitral Valve 175 



apparently meaningless facts, and occasionally aided 

 his memory by inventing for them a humorous signif- 

 icance. Professor Howes relates a story of this kind. 

 While examining the papers of candidates for some 

 examination, Huxley came across one in which the 

 mitral or bicuspid valve of the heart was erroneously 

 described as being placed in the right cavity, " Poor 

 little beggar," said Huxley; "I never could get 

 them myself until I reflected that a bishop could never 

 be in the right." This insistence on the uselessness 

 of formal knowledge applied only to those who were 

 being taught or who were learning from books or 

 lectures. Of the value and discipline of knowledge of 

 facts gained at first hand from objects themselves 

 either in original investigation or with the aid of 

 books, Huxley had the highest possible opinion. By 

 such a method of work alone he believed it possible to 

 distinguish what we believe on authority from what 

 we have convinced ourselves to be true, and, as we 

 shall see later, he regarded it as the most important 

 duty of a man to have acquired the habit of classifying 

 the mass of ideas in his brain into those which he 

 knew and those which he thought to be true from 

 having read or heard or imagined them. 



The two other of the three great treatises for 

 anatomical students are the Manual of the Ayiatomy 

 of Vertebrated Animals, published in 187 1, and the 

 Manual of the Anatomy of Invertebratcd Animals, 

 published in 1877. Of these two volumes it is suffi- 

 cient to say that they formed the chief introduction to 

 the study of animal zoology for many years, and that 

 a large number of the best-known zoologists of the end 

 of this century received from them their first instruc- 

 tion in the science. As text-books they have been 



