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pure cultures. These would increase in numbers and complexity 
as the science develops, and we might then expect to be in a position 
to investigate bacterial processes, as they occur in nature, more 
fairly and with greater success. 
Harriette Chick. 
THE PRINCIPLES OF MORPHOLOGY.—I. 
Introduction. 
It is by a study of the evolution of the forms of life composing 
the vegetable kingdom that the science of morphology has been 
gradually built up. It is a study exceedingly important in itself, 
and quite distinct from that of physiology, which deals solely with 
the functions which those various structures perform. 
The principles of morphology are the inherent and essential 
laws governing the production of form in the vegetable world, 
which we deduce by means of a study of the phylogenetic sequence 1 
(or what we regard as such) of forms through family after family 
of plants. 
As regards the external conformation of the typical plant, I 
believe myself that an exceedingly limited number of fundamentally 
discrete and individually distinctive organs (organs sui generis ) 
occur which have been laid down as such from nearly the 
commencement of the plant’s evolution, viz. the caulome, phylloine , 
and rhizome , 2 for it seems quite possible to trace these under their 
innumerable and infinitely varying forms from the earliest and 
most primitive types onward to the very highest; and not only that, 
but also along all the distinct phyla into which the Vegetable 
Kingdom has become split. And hence, to take an illustration, we 
should expect homologous organs to occur, in each of the great 
phyla, Lycopods, Equisetacete, Ferns and Flowering Plants, at 
every stage in the individual life-history of the plant. The 
“ morphology ” of any doubtful organ would hence be often arrived 
at by means of a close comparative study of related organs (or what 
we regard as such) throughout the entire range of vascular plants. 
This comparison must necessarily be exceedingly fundamental and 
1 It is just here where, in the absence of perfect objective 
continuity of the forms concerned, the subjective interpretation 
of such facts as arc available, plays so predominant a part. 
2 This word is here used in its literal, original sense, not in that 
of our text-books. 
