MANY OR ONE ANCESTRAL STOCKS ? 45 
to trace the first origin of all individual groups of organisms, 
as well as their totality, to a single common species of 
Moneron which originated by spontaneous generation (vol. i. 
p. 343). The multiple, or polyphyletic, hypothesis of descent, 
on the other hand, will assume that several different species 
of Monera have arisen by spontaneous generation, and that 
these gave rise to several different main classes (tribes, or 
phyla) (vol. i. p. 348). The apparently great contrast between 
these two hypotheses is in reality of very little importance. 
For both the monophyletic and the polyphyletic hypothesis of 
descent must necessarily go back to the Monera as the most 
ancient root of the one or of the many organic tribes. But 
as the whole body of a Moneron consists only of a simple, 
formless mass, without component particles, made up of a 
single albuminous combination of carbon, it follows that the 
differences of the different Monera can only be of a chemical 
nature, and can only consist in a different atomic com- 
position of that mucous albuminous combination. But 
these subtle and complicated differences of mixture of the 
infinitely manifold combinations of albumen are not appre- 
ciable by the rude and imperfect means of human observation, 
and are, consequently, at present of no further interest to 
the task we have in hand. 
The question of the monophyletic or polyphyletic origin 
will constantly recur within cach individual tribe, where 
the origin of a smaller or of a larger group is discussed. In 
the vegetable kingdom, for example, some botanists will be 
inclined to derive all flowering plants from a single form of 
fern, while others will prefer the idea that several different 
groups of Phanerogama have sprung from several different 
groups of ferns. In like manner, in the animal kingdom, 
