PREFACE. 



In the following pages the Author's aim has been to 

 deal with the Study of Structural and Physiological 

 Botany from a biological standpoint, in which the work- 

 ing substance of a cell, — viz., the protoplasm — is given 

 the first place in importance ; the subsequent changes 

 which are produced in form, function, &c., being looked 

 upon as being due to the sole agency of the protoplasm, 

 influenced by the various physical and chemical stimuli 

 which may be brought to bear upon it. This method 

 of dealing with the cell, whether animal or vegetable, 

 has been found, in the writer's experience, to be a 

 rational and useful one when such a wide subject as 

 Biology is first approached by the student. The section 

 on Cell-division has been presented in rather full detail, 

 on account of the great importance attached nowadays 

 to cytological phenomena in which the nucleus is in- 

 volved. With regard to the illustrations, a few photo- 

 micrographs have been inserted, and these, it is hoped, 

 will give a rather more realistic aspect to one or two of 

 the more difficult sections, such as those on Embryology 

 and Nuclear Division. 



The Author's thanks are due to Professor Oliver 

 (University College, London) for several valuable sug- 

 gestions, and for the help afforded whilst the Author 

 was a student at University College. 



H. A. H. 



Hendon, 1909. 



