INTRODUCTION. XXX iii 



given individual or species ; it carries us back some 

 stages further in the history of particular organisms, 

 but so also does teratology. Many cases of arrest of 

 development show the mode of growth and evolution 

 more distinctly, and with much greater ease to the 

 observer, than does the investigation of the evolution of 

 organs under natural circumstances. Organogeny by 

 no means necessarily, or always, gives us an insight into 

 the principles regulating the construction of flowers in 

 general. It gives us no archetype except in those 

 comparatively rare cases where primordial symmetry 

 and regularity exist. When an explanation of the 

 irregularity of development in these early stages of 

 the plant's history is required, recourse must be had 

 to the inferences and deductions drawn from tera- 

 tological investigations and from the comparative 

 study of allied forms precisely as in the case of adult 

 flowers. 



The study of development is of the highest import- 

 ance in the examination of plants as individuals, but 

 in regard to comparative anatomy and morphology, 

 and specially in its relation to the study of vegetable 

 homology it has no superiority over teratology. Those 

 who hold the contrary opinion do so, apparently, be- 

 cause they overlook the fact that there is no distinction, 

 save of degi'ee, to be drawn between the laws regulating 

 normal organisation, and those by which so-called 

 abnormal formations are regulated. 



It is sometimes said, and not wholly without truth, 

 that teratology, as it stands at present, is httle more 

 than a record of facts, but in proportion as the laws 

 that regulate normal growth are better understood, 

 so will the knowledge of those that govern the so- 

 called monstrous formations increase. Sufficient has 



