4 EVOLUTIONS OF ORGANIZATION. 
with the phenomena of life, and learns the me- 
chanical and chemical processes involved in them, 
he. naturally asks how far the laws of life are to 
be explained by the laws of matter, and what is 
the motive power of the order of phenomena both 
in the individual and in the series. There come up 
for his consideration the links uniting to the body 
that spiritual element which, in the actions of the 
individual, is never seen by us in operation, save 
in the closest association with physical structure. 
And the yet larger speculation, Is spirit or matter 
the prior, the underlying, unchangeable, and eternal 
element, constantly obtrudes itself on the horizon 
of more limited inquiries. 
These are all questions which have been much 
discussed in recent times; and the order of the 
appearance of structures having been studied both 
in the form of paleontology and development, it is 
not wonderful that speculations have been rife as 
regards not only the nature, but likewise the origin 
of life, of species, of matter, and intelligence. 
That there is a certain unity binding together 
the most diverse forms of organization is a doctrine 
which, at this date, I fancy no one will deny. The 
similarity of the units of life in plant and animal 
texture, and the general, if not altogether universal, 
pervasion of sexual distinction, are illustrations of 
ek ae 
