THE BELFAST ADDRK8S. 479 
inorganic,* and afterward with profound insight to organic 
nature. The vegetable world, though drawing all its 
nutriment from invisible sources, was proved incompetent 
to generate anew either matter or force. Its matter is for 
the most part trans tnu ted gas; its force transformed solar 
force. The animal world was proved to be equally un- 
creative, 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 mole- 
cules. The muscles were shown to be stores of mechanical 
energy, 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 by 
Helmholtz, and found to be, not, as had been previously 
supposed, equal to that of light or electricity, but less than 
the speed of sound less even than that of an eagle. 
This was the work of the physicist: then came the con- 
quests 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 zoo4>liyte 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 growth 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 
* Dr. Bertbold has shown that Leibnitz had sound views regarding 
the conservation of energy in inorganic nature. 
