THOUGHTS ON NATURAL PHILOSOPHY. 29 
The great physiologist Verworn writes that :—‘ The fact 
stands out clearly and distinctly that life from its beginning 
has been dependent upon the external conditions of the 
earth’s surface. In a mathematical sense, life is a function 
of the earth’s development. Living substance could not exist 
while the earth was a molten sphere without a solid, cool, 
crust ; it was obliged to appear with the same inevitable 
necessity as a chemical combination when the necessary 
conditions were given; and it was obliged to change its form 
and its composition in the same measure as the external 
conditions of life changed in the course of the earth’s develop- 
ment. It is only a portion of the earth’s matter. The 
combination of this matter into living substance was as much 
the necessary product of the earth’s development as was the 
origin of water. It is an inevitable result of the progressive 
cooling of the masses that formed the earth’s crust. Like- 
wise, the chemical, physical, and morphological character- 
istics of existing living substance are the necessary result of 
the influence of the external conditions of life upon the 
internal relations of past living substance. Internal and 
external vital conditions are inseparably correlated, and the 
expression of this correlation is lfe.’’ The whole being 
caused by material motion. When the earth and its sur- 
roundings are sufficiently cold, when material motion is too 
feeble for the manifestation of life, vital phenomena on this 
planet will cease to exist. 
The subject is so vast and so exquisitely beautiful that one 
might write for ever, and there is a danger of eloquent gush ; 
but I spare the reader. 
Some persons may fear to amend the Newtonian 
philosophy, lest some great catastrophe happen. They may 
argue: “ How can I give up this idea? What was to keep 
matter together before this universe was evolved, and what 
