II Some of the " Best Books " on A?mnal Life 365 



C, Biology. 



Having offered counsel to those who would study the literature 

 of Zoology and of Natural History, I shall complete my task of 

 giving advice by addressing those who are strong enough to 

 inquire into the nature, continuance, and progress of life. It is 

 to students of mature years that this "biological" study is most 

 natural, for young folks should be left to see and enjoy as much 

 as possible, till theories grow in them as naturally as "wisdom 

 teeth." This also should be noted in regard to the study of 

 evolution and the related problems of biology, that though all the 

 generalisations reached must be based on the research and observa- 

 tion of zoologists, botanists, and naturalists, and are seldom fully 

 appreciated by those who have little personal acquaintance with 

 the facts, yet sound and useful conclusions may be, and often are, 

 obtained by those who have had no discipline in concrete scientific 

 work. 



Besides the general question of organic evolution there are 

 special subjects which the student of biology must learn to think 

 about: Protoplasm, or "the physical basis of life;" Repro- 

 duction, Sex, and Heredity, or "the continuance of life;" and 

 Animal Intelligence, or "the growth of mind." Before passing 

 to the literature on these subjects, it may be noted that there are 

 two general works of pioneering importance, namely, Herbert 

 Spencer's Principles of Biology (2 vols., Lond., 1864-66), and 

 Ernst Haeckel's Generelle Morphologic (2. vols., Berlin, 1866). 



Protoplasm. — Of this the student should learn how little we 

 know. Yet this is not very easy, since the most important recent 

 contributions, such as those of Professors Hering and Gaskell, are 

 inaccessible to most. The gist of the matter, however, may be 

 got hold of by reading : (a) three articles in the Encyclopedia 

 Britannica, "Physiology" (Prof. M. Foster), "Protoplasm" 

 (Prof. P. Geddes), and " Protozoa" — the large type— (Prof. E. Ray 

 Lankester) ; (/>) the Presidential Address to the Biological Section 

 of the British Association, 1889, by Prof. Burdon Sanderson 

 {Nature, xl., September 1S89, pp. 521-526); and [c) the article 

 "Protoplasm" in the new edition of Chambers's Encyclopcedia. 

 Of the abundant literature on the philosophical questions which 

 the scientific conception of living matter raises, I shall mention 

 Huxley's address on "The Physical Basis of Life," published 

 among his collected essays; Hutchison Stirling's tract, "As 

 regards Protoplasm;" the chapter on "Vitalism" in ^^Bunge's 

 Physiological Chemistry (translated, London, 1890). 



Reproduction, Sex, and Heredity. — For adult students, 

 and no others should be encouraged to face the responsibility of 



