THE RECAPITULATION THEORY 175 
genetic and cenogenetic phenomena must be sifted apart, an operation 
which required more than one critical grain of salt. On what grounds 
shall this critique be based? Assuredly not by way of a vicious circle 
on the ontogeny again; for if cenogenetic characters are present in one 
case, who will guarantee that a second case, used for a comparison with 
the first, does not likewise appear in cenogenetic disguise? If it once 
be admitted that not everything in development is palingenetic, that 
not every ontogenetic fact can be accepted at its face value, so to 
speak, it follows that nothing in ontogeny is immediately available 
for the critique of embryonic development. The necessary critique 
must be drawn from another source.” 
These remarks of Gegenbaur’s were called forth by the state of 
wild speculation into which embryological work had fallen. As there 
were no generally accepted canons of interpretation for the facts of 
embryological development, different writers interpreted these facts 
in the most divergent and contradictory manner, resulting in a chaotic 
confusion, which led to a strong reaction against the whole method, 
though there can be little doubt that this reaction has gone too far. 
“Tt must be evident to any candid observer, not only that the 
embryological method is open to criticism, but that the whole fabric 
of morphology, so far as it rests upon embryological evidence, stands 
in urgent need of reconstruction. For twenty years embryological 
research has been largely dominated by the recapitulation theory; 
and unquestionably this theory has illuminated many dark places and 
has solved many a perplexing problem that without its aid might have 
remained a standing riddle to the pure anatomist. But while fully 
recognizing the real and substantial fruits of that theory, we should not 
close our eyes to the undeniable fact that it, like many another fruit- 
ful theory, has been pushed beyond its legitimate limits. It is largely 
to an overweening confidence in the validity of the embryological 
evidence that we owe the vast number of the elaborate hypothetical 
phylogenies which confront the modern student in such bewildering 
confusion. The inquiries of such a student regarding the origin of any 
of the great principal types of animals involve him in a labyrinth of 
speculation and hypothesis in which he seeks in vain for conclusions 
of even an approximate certainty.” 
Many other equally vigorous and well-deserved criticisms of the 
embryological method might be cited, but it should be emphasized that 
these criticisms are all directed against the application of the method 
to the solution of definite and concrete problems of descent and 
