“I remember,” he wrote, “in my youth there were detestable books which ought to have been burned by the hands of the common hangman, for they contained questions and answers to be learned by heart, of this sort, ’What is a horse?  The horse is termed Equus caballus; belongs to the class Mammalia; order, Pachydermata; family, Solidungula.’  Was any human being the wiser for learning that magic formula?  Was he not more foolish inasmuch as he was deluded into taking words for knowledge?”

Huxley himself admitted his difficulty in remembering apparently meaningless facts, and occasionally aided his memory by inventing for them a humorous significance.  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 Anatomy of Vertebrated Animals, published in 1871, and the Manual of the Anatomy of Invertebrated Animals, published in 1877.  Of these two volumes it is sufficient to say that they formed the chief introduction to the study of animal zooelogy for many years, and that a large number of the best-known zooelogists of the end of this century received from them their first instruction in the science.  As text-books they have been superseded lately by larger volumes in which there is found more space for some of the recent advances in knowledge, especially comparative embryology, and the more intricate knowledge of the structure of the soft parts of marine invertebrates made possible by the newer and more successful methods of preserving delicate tissues.  Just before Huxley ceased his regular work as a teacher at the Royal College of Science, there arrived a series of marine embryos, beautifully preserved and prepared for microscopic work by the zooelogists at the International Zooelogical Station at Naples.  Huxley is reported to have exclaimed at their beauty, and to have said: