THE CELL THEORY 241 
whether it is examined in the vegetating point of a plant, or 
in the young budding organs of an animal.” 
Wolff was contending against the doctrine of pre-forma- 
tion in the embryo (sce further under the chapter on Embry- 
ology), but on account of his acute analysis he should be 
regarded, perhaps, as the chief forerunner of the founders of 
the cell-theory. He contended for the same method of de- 
velopment that was afterward emphasized by Schleiden and 
Schwann. Through the opposition of the illustrious physi- 
ologist Haller his work remained unappreciated, and was 
finally forgotten, until it was revived again in 1812. 
We can not show that Wolff’s researches had any direct in- 
fluence in leading Schleiden and Schwann to their announce- 
ment of the cell-theory. Nevertheless, it stands, intellectually, 
in the direct line of development of that idea, while the views 
of Haller upon the construction of- organized beings are a 
side-issue. Haller declared that ‘the solid parts of animals 
and vegetables have this fabric in common, that their ele- 
ments are either fibers or unorganized concrete.” This 
formed the basis of the fiber-theory, which, on account of the 
great authority of Haller in physiology, occupied in the 
accumulating writings of anatomists a greater place than 
the views of Wolff. 
Bichat, although he is recognized as the founder of his- 
tology, made no original observations on the microscopic units 
of the tissues. He described very minutely the membranes 
in the bodies of animals, but did not employ the microscope 
in his investigations. 
Oken.—In the work of the dreamer Oken (1779-1851), 
the great representative of the German school of ‘“‘ Natur- 
philoso phie,” we find, about 1808, a very noteworthy state- 
ment to the effect that “animals and plants are throughout 
nothing else than manifoldly divided or repeated vesicles, as 
I shall prove anatomically at the proper time.” This is 
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