124 
JOURNAL OF THE PLYMOUTH INSTITUTION. 
AN UNNAMED FACTOR IN ORGANIC 
CONSTRUCTION. 
ABSTRACT OF PAPER BY MR. F. H. BALKWILL, M.O.S. 
(Read March 13th, 1879.) 
The evidence afforded by the independent concurrent testimony of 
the sciences of astronomy, geology, geography, and biology, the 
latter including palaeontology, anatomy, physiology, embryology, 
and histology, each science or branch of science being the product 
of the accumulation of an immense number of facts by a great 
number of workers, all tending in the same direction, makes a 
theory of evolution necessary at the present time. In fact it seems 
impossible to think connectedly in any other manner. At the same 
time it is not proved that life ever spontaneously arose out of that 
which had no life ; and there is no more a priori reason for in- 
cluding such a supposition in the theory of evolution than there is 
for supposing that a very subtle form of matter spontaneously arose 
out of nothing, as a preparatory step to the nebular hypothesis in 
astronomy. Neither is it necessary to a theory of evolution to 
believe that there was an unbroken hereditary line between the 
lowest form of life and the highest. This may be the fact, or it 
may not ; as, for instance, the question whether man is descended 
from the ape has as yet received no affirmative answer in the 
finding of any intermediate types. As in geography it is well 
understood that all the land on the globe has a solid connection 
either above or under water, but still each island and continent 
requires special survey to inform us of its special shape and con- 
nections above water ; so in the science of evolution as applied to 
animal life, we feel assured that there is some connection linking 
the whole, yet still we require that each species or genera shall be 
distinctly surveyed to note its connections ; and where facts are not 
forthcoming must be content to hold our judgment. 
