xvi PREFACE. 



being investigated some forbearance may, perhaps, not 

 unfairly be claimed for certain literary defects and in- 

 consistencies, which were to some extent unavoidable. 

 For although this order was definitely planned, yet it 

 has happened that more than three-fourths of the work 

 was actually printed before the new investigations de- 

 tailed in the latter part were made and certainly at a 

 time when I had scarcely hoped ever to witness such 

 transformations as I have since been able to follow. 



I am deeply impressed with the conviction that we 

 are but upon the threshold of our acquaintance with 

 these marvellous heterogenetic transformations, the 

 discovery of which already affords material for revolu- 

 tionizing the old foundations of botanical and zoological 

 science. But the path now opened must be followed 

 up by other workers by faithful and competent ob- 

 servers who are willing zealously to watch and wait 

 through eager hours whilst Nature unfolds her secret 

 processes by those true students who, instead of being 

 blinded by any existing theories, are content to regard 

 them as useful and modifiable aids to further progress. 



QUEEN ANNE STREET, CAVENDISH SQUARE, 

 May 21, 1872. 



