PREFACE. 



BY way of preface to this volume it may not, perhaps, be 

 out of place to state briefly the motives which have 

 prompted me to attempt what has proved to be a task of 

 no small difficulty. A not inconsiderable experience as a 

 university teacher of Biology has convinced me that in order 

 to properly appreciate and benefit by a study of that science 

 a student must first undergo a preliminary training in the 

 facts and conclusions of Physics and Chemistry, and in ad- 

 dition must devote not a little time and labour to studying 

 the application of the more general laws of these sciences 

 to the special phenomena of plant and animal life. It is 

 however by no means an easy matter for a beginner in the 

 subject to select from the vast domain of the physical 

 and chemical sciences those generalisations which have an 

 immediate bearing on the problems of Biology. I have 

 therefore endeavoured to summarise briefly in a preliminary 

 chapter the principal conclusions of the inorganic sciences, 

 devoting special attention to those laws on which the higher 

 science of Biology is founded. It is scarcely necessary to 



