8 2 
The Course of Nature. 
[January, 
earth ; that gunpowder, when touched by fire, suddenly 
changes to an incandescent gas ; that water, at or- 
dinary pressure, changes to steam at a temperature of 212 0 . 
Now, scientific investigators are earnestly endeavouring, 
each in his own sphere, to do for the whole of nature what 
Newton did for the laws of planetary motion, to find and 
announce the elementary principles which connect all the 
links of the endless chain which sjunbolises her course. 
The student of chemistry cannot doubt that the innumer- 
able properties of the various compounds which he studies 
arise from the play of certain attractive and repulsive forces 
among the elementary molecules of the matter of which 
these compounds are formed. Could he only learn the law 
according to which these forces aCt, chemistry might become 
very largely a deduCtive science, and the properties of com- 
pounds might be predicted in advance, as the astronomer 
predicts the conjunctions of the planets. The idea now 
entertained by those who see farthest in this direction is 
that all the physical properties of matter depend upon, and 
may be reduced to, certain attractive and repulsive forces 
acting among the ultimate atoms of which matter is 
composed. 
It may also be supposed that all the operations of the 
vital organism, both in men and animals, depend in the 
same way upon molecular forces among the atoms which 
make up the organism. The operation of forces unknown 
to chemistry must, indeed, be presupposed, but there is no 
reason to suppose that these forces are less simple than 
chemical ones. Some would even go so far as to explain 
the faCts of consciousness in this way. The philosophy 
of this explanation belongs, however, to another depart- 
ment of thought — that of scientific materialism — into which 
we cannot at present enter. 
The most startling attempts in the direction I have 
indicated are those which are designed to show that those 
wonderful adaptations which we see in the structure of 
living animals, and which in former times were attributed 
to design, are really the result of natural laws, aCting with 
the same disregard to consequences which we see in the 
falling rock. The philosophy of Darwinism, and the theory 
of evolution, will be at once brought to your mind as form- 
ing the modern system of explanation tending to this result. 
On these theories the eye was not made in order to see, nor 
the ear in order to hear, nor are the numberless adaptations of 
animated beings to the conditions which surround them in 
any way the product of design. Absurd as this theory 
appears at the first glance, and great as is the anxiety to 
