PREFACE 



BIOLOGY, the fundamental science of living things in all their 

 manifold relations, is a study which, at the present time, is but 

 little encouraged by educational authorities in this country. It 

 has no place in the ordinary school curriculum and even in our 

 Universities it has been thrust into the background, partly 

 because University authorities devote so much of their attention 

 nowadays to subjects which are considered more likely to 

 bring in a direct pecuniary reward to the student, and partly 

 because of the immense elaboration of the various branches of 

 biological science, such as Zoology, Botany, Physiology, Com- 

 parative Anatomy and Embryology, that has taken place in 

 recent years, and the claims of these to more or less separate 

 recognition. 



The student, if he studies Biology at all for its own sake, 

 which is seldom the case, usually confines himself almost 

 entirely to one or other of these branches, which he finds 

 treated more or less as an independent science, with an extensive 

 literature of its own, and he runs a grave risk of losing sight of 

 the general principles which underlie all and from which all 

 derive their chief educational value. 



The medical student, it is true, usually takes a year's course 

 in what is called Biology, but his curriculum is, perhaps 

 unavoidably, dominated by the type-system and by what is 

 thought likely to be of direct service to him in his future 

 anatomical and physiological studies, so that in the brief time 

 which the medical authorities allow him to devote to the 

 scientific foundation of his professional work he has but little 

 opportunity for a philosophical treatment of the subject. 



When we at length come to realize the meaning of Man's 

 position as, for the time being, the highest term of a great 

 evolutionary series which stretches far back into the dawn of 



