1893.] Physiology and Morphology. 807 
doctrine of preformation, or pre-existence of organisms in the 
germ, and the notion of the inclusion of one germ preforma- 
tion within another, was certainly strongly suggested by the 
unfolding of plant buds and by the metamorphoses of insects ; 
but as soon as it became possible to examine more minutely 
the phases of development, it was found that the fine-spun 
theories of Bonnet and Haller were refuted by morphological 
facts, and the doctrine of epigenesis, defended by Aristotle and 
Harvey, was led to triumph through the observations of Cas- 
par Friedrich Wolff. 
- Our special senses have afforded one of the most fertile 
fields for speculative physiology. It is needless to dwell on 
antiquated hypotheses of * vital spirits " residing in the nerves, 
of a subtle nervous humor, or *imponderable fluid " drawn 
from the blood and secreted by medullary matter (Cuvier). 
The history of the hypotheses of life, sensation and volition 
are largely, as Whewell has well remarked, “ the story of the 
failures of physiological speculation.” It is to the cultivation 
of the morphological sciences that physiology owes in a very 
large measure, its deliverance from the temptation to stray 
into the region of metaphysics. 
As morphology furnishes the ground structure on which 
physiology operates, it naturally takes the place of pioneer 
and guide; but if permitted to wander too far in advance, it 
soon finds itself entangled with physiological problems with 
which it is not prepared to cope, and its efforts to release itself 
often end in sterile speculation. The workers on both sides 
should therefore advance abreast, in hand to hand contact. 
It is only in such reciprocally helpful relations that specialists 
can attain the highest possible individual development, and 
it is only when morphological and physiological experience 
and knowledge combine, that biology can accomplish such 
brilliant feats as that of Cuvier in reconstructing an extinct 
organism from its fragmentary remains. 
The association of morphological and physiological research 
enlarges the field of vision on both sides, reduces the chances 
of useless labor, corrects false notions, stimulates inquiry, con- 
verts half views into whole views, and withal secures mutual 
respect. 
