22 GENESIS OF MAN. 



The entire body of principles embraced in the Lamarckian, Dar- 

 winian, and Haeckelian philosophy, when regarded as having passed 

 through its hypothetical and theoretical stages, takes the form of a 

 science, and receives the very "appropriate name, History of De- 

 velopment (Entwickclnngsgcschichtc), a term adopted by Von Baer 

 and applied to embryonic development, but extended by Haeckel 

 to embrace also the secular development of specific forms. This 

 twofold application of the term History of Development, suggests 

 the natural division of the science into its two great departments. 

 The first of these is essentially that of Von Baer, and treats of the 

 progress of the individual organism from the earliest embryonic 

 condition throughout the numerous successive stages and trans- 

 formations through which it passes until it arrives at the perfect 

 state. Properly it does not stop at birth, but continues through 

 life, during which, in many creatures, very important metamorphoses 

 take place. This division of the History of Development is de- 

 nominated Ontogeny. The other grand division, which treats of 

 the development of present living forms out of antecedent forms 

 through the influences of heredity ( Vererbung) and adaptation 

 (Anpassiing), is termed Phytogeny, a term derived from the Greek 

 word <puXov, a race. 



It is to this latter branch of the History of Development that 

 the attention of progressive minds has been heretofore almost ex- 

 clusively directed, and the arguments of Lamarck and Darwin have 

 been chiefly drawn from considerations of comparative anatomy, 

 of geographical distribution, and of paleontology. The powerful 

 re-enforcement which it has now received from ontogeny was quite 

 unexpected, and the astonishing uniformity with which the onto- 

 genetic facts support, confirm, and corroborate the phylogenetic 

 arguments, may be regarded as having placed the doctrine of 

 development beyond the stage of theory and speculation, and 

 established it as the first law of Biology. 



Although the chief facts of ontogeny had been discovered and 

 recorded by Von Baer and others, a quarter of a century before, it 

 was left for Haeckel to first perceive and announce their relation to 

 the law of phylogenetic development, and to urge their irresistible 

 force as arguments for the theory of descent. Von Baer himself, 

 although he had erected them into a " History of Development," 

 seems but dimly to have realized the significance of these embry- 



