]XXXvlli REPORT—1874. 
radical significance, is the doctrine of the Conservation of Energy, the ulti- 
mate philosophical issues of which are as yet but dimly seen—that doctrine 
which ‘binds nature fast in fate” to an extent not hitherto recognized, 
exacting from every antecedent its equivalent consequent, from every con- 
sequent its equivalent antecedent, and bringing vital as well as physical 
phenomena under the dominion of that law of causal connexion which, so far 
as the human understanding has yct pierced, asserts itself everywhere in nature. 
Long in advance of all definite experiment upon the subject, the constancy 
and indestructibility of matter had been affirmed; and all subsequent expe- 
rience justified the affirmation. Later researches extended the attribute of 
indestructibility to force. This idea, applied in the first instance to inorganic, 
rapidly embraced organic nature. The vegetable world, though drawing 
almost all its nutriment from invisible sources, was proved incompetent to 
generate anew either matter or force. Its matter is for the most part trans- 
muted gas; its force transformed solar force. The animal world was proved 
to be equally uncreative, all its motive energies being referred to the com- 
bustion of its food. The activity of each animal as a whole was proved to be 
the transferred activity of its molecules. The muscles were shown to be 
stores of mechanical force, potential until unlocked by the nerves, and then 
resulting in muscular contractions. The speed at which messages fly to and 
fro along the nerves was determined, and found to be, not as had been previ- 
ously supposed, equal to that of light or electricity, but less than the speed 
of a flying eagle. 
This was the work of the physicist: then came the conquests of the 
comparative anatomist and physiologist, revealing the structure of every 
animal, and the function of every organ in the whole biological series, from 
the lowest zoophyte up to man. The nervous system had been made the 
object of profound and continued study, the wonderful and, at bottom, entirely 
mysterious controlling power which it exercises over the whole organism, 
physical and mental, being recognized more and more. Thought could 
not be kept back from a subject so profoundly suggestive. Besides the 
physical life dealt with by Mr. Darwin, there is a psychical life presenting 
similar gradations, and asking equally for a solution. How are the different 
grades and orders of Mind to be accounted for? What is the principle of 
erowth of that mysterious power which on our planet culminates in Reason ? 
These are questions which, though not thrusting themselves so forcibly 
upon the attention of the general public, had not only occupied many 
reflecting minds, but had been formally broached by one of them before the 
‘ Origin of Species’ appeared. ; 
With the mass of materials furnished by the physicist and physiologist in 
his hands, Mr. Herbert Spencer, twenty years ago, sought to graft upon this 
basis a system of psychology ; and two years ago a second and greatly ampli- 
fied edition of his work appeared. Those who have occupied themselves 
with the beautiful experiments of Piateau will remember that when two 
spherules of olive-oil suspended in a mixture of alcohol and water of the 
same density as the oil, are brought together, they do ‘not immediately 
unite. Something like a pellicle appears to be formed around the drops, 
the rupture of which is immediately followed by the coalescence of the 
globules into one. There are organisms whose vital actions are almost 
as purely physical as that of these drops of oil. They come into contact 
and fuse themselves thus together. From such organisms to others a shade 
higher, and from these to others a shade higher still, and on through an 
eyer ascending series, Mr, Spencer conducts his argument, There are two 
