Origin and Development of the Composite. 67 
Bergson h*as yet attempted to expound a synthetic theory. This 
exposition by Bergson of evolution (7) is only partly scientific; it is 
rather metaphysical and transcendental as beseems the work of a 
philosopher. It is, however, of the greatest importance to the 
student of evolution who desires to appreciate the true meaning of 
the development and progress of life. 
Perhaps this brings the expression “ life force ” to the mind 
of the reader; if so it is necessary to point out that the original 
phrase “ un elan de la vie” is translated by “ vital impetus” or 
“ impulse of life ” and not by “ life force.” These phrases give a 
better idea of what Bergson means than the popular “ life force ” 
does (cp. 47). 
According to Bergson (op. cit., p. 103) evolution “ proceeds 
rather like a shell, which suddenly bursts into fragments, and these 
fragments, being themselves shells, burst in their turn into fragments 
destined to burst again, and so on for a time incommensurably long. 
We perceive only what is nearest to us, namely, the scattered move¬ 
ments of the pulverized explosions.” 
Other general accounts of less importance are given by Bernard 
(8) and the writer (47), and various aspects are treated by different 
authors in Darwin and Modern Science (45). 
Natural Selection. 
The theory of the origin of species by the elimination of all 
except the fittest of a series of infinitesimal variations (II, 16) has 
been widely accepted since 1858, but few recent experimentalists 
support this view, although not many deny it altogether. 
One of the few supporters is Stout (50-51) but there is much in 
his work on Cichorium that requires revision. For example, he 
makes a strong point of the fact that the mode of the flower number 
per head in Cichorium does not fall in the Fibonacci series. The 
vast majority of the data refer to the ray florets (which are not 
present in Cichorium) and, as Church (IV, 18, p. 116) has shown, 
the Fibonacci series in the number of rays depends on the 
number of long spirals in the inflorescence and the sub-division of 
these spirals according to the 2 : 1 : 2 : 1 : 2 arrangement (see Chap. 
VIII). The number of spirals in the disc is definite and usually 
in the Fibonacci series but the number of flowers in each spiral is 
very indefinite (cp. IV, 18, p. 133). There is, therefore, no 
apparent reason why the total flower number per head should be in 
the Fibonacci series or discontinuous at all, although the discon 
