An Historical Sketch. 
7i 
the ovary of the Primulaceae is another example, affording us excellent 
proof of the unreliability of developmental evidence in such cases. The 
comparative method is a useful one, but taken alone is not finally reliable, 
for the standard of comparison is likely to be ever a shifting quantity 
varying with each botanist who employs it ; indeed, it seems impossible 
to apply this method by itself to the solution of the nature of an obscure 
structure like the ovule. The Bohemian Professor further regards anatomi- 
cal data as powerless when directed to the same purpose ; Van TieghenTs 
method of research along these lines must be regarded as stilted and 
artificial ; for vascular tissue is developed where it is needed and is quite 
independent of the morphological character of the organ which it supplies, 
and no absolute reliance is to be placed on the character of the course 
or structure of the bundles. Yet all three of these methods may be 
usefully employed as collateral aids and adjuncts in solving the morphology 
of a doubtful structure. For this latter purpose, however, the direct and 
principal method is that of the study of teratological phenomena ; it is on 
the ‘ metamorphogenesis ’ that Celakovsky rests the whole weight of 
his argument ; for he maintains that these abnormalities, or deviations 
from the normal structure, are not of the nature of ‘sports’ or ‘ monstrosi- 
ties,’ as is usually supposed, but, on the contrary, are phenomena controlled 
by definite laws of development, producing thereby structures which are 
not new or monstrous (except, indeed, as regards the limited life-cycle of 
the particular organisms or group of organisms concerned), but whose 
homologues will inevitably be found occurring as normal structures in 
organisms belonging to other sections of the vegetable kingdom. For 
all vegetable life is one, and the four types of organs : caulome, root, 
phyllome, and trichome, are the common heritage of all members of the 
vegetable world. But the question arises: how is the morphological 
value of any given doubtful organ to be determined by means of the 
abnormal structure which it assumes under the influence of these laws of 
‘metamorphogenesis’? It would not be justifiable, on the ground of a 
mere supplanting or replacement of the abnormal structure, to regard the 
two as homologous in nature. But if (and this the writer regards as 
Celakovsky’s unassailable position) there can be traced in the metamorpho- 
genesis a series of gradual transitions (whether occurring in a single in- 
dividual or scattered over a number of individuals, matters not) between 
the normal form and the extreme stage of the metamorphosed structure 
replacing it, then this must prove the absolute homology of the two, i. e. 
that they possess an identical morphological value. It seems to the writer 
that a certain shallowness of thought and the influence of preconceived 
ideas on the subject are the cause of the rigid adherence by so many 
eminent botanists to the oft-reiterated statement that ‘ abnormalities can 
be made to prove anything ’ ! It betrays an utter neglect of the possibility 
