L I B R A It 



UNIVERSITY OF 



CALIF [A. 



PREFACE. 



VERY soon after I began to teach Natural History, or what 

 we now call Biology, at the Royal School of Mines, some 

 twenty years ago, I arrived at the conviction that the study 

 of living bodies is really one discipline, which is divided into 

 Zoology and Botany simply as a matter of convenience; and 

 that the scientific Zoologist should no more be ignorant of 

 the fundamental phenomena of vegetable life, than the scien- 

 tific Botanist of those of animal existence. 



Moreover, it was obvious that the road to a sound and 

 thorough knowledge of Zoology and Botany lay through 

 Morphology and Physiology; and that, as in the case of all 

 other physical sciences, so in these, sound and thorough 

 knowledge was only to be obtained by practical work in 

 the laboratory. 



M. I 



