24 THE VICTORIAN NATURALIST. 



places. They are the doctrines of Evolution and of the Conser- 

 vation of Energy. 



The first of these we owe to the unwearied patience and pro- 

 found researches of Charles Darwin, who in 1859 pubhshed his 

 " Origin of Species," and startled the world alike by the wondrous 

 collection of facts that he brought together, and the deductions 

 drawn from these facts. Like many another new thing, it was 

 received at first with bitter opposition, then with calm con- 

 sideration, and is to-day, I suppose, accepted by the great bulk of 

 the scientific world ; at any rate, if not absolutely proven, yet so 

 far proven as to form a capital theory to work by. Mr. Darwin's 

 theory of variation by natural selection is so well known to all of 

 us that I need not stay 10 explain it. It works a complete revolu- 

 tion in our ideas of the mode in which succeeding races of plants 

 and animals have appeared on our earth. 



Quite as startling as the doctrine of evolution is ihat of the 

 conservation of energy, concerning which Professor Tyndall says 

 — " A doctrine which exacts from every antecedent its equivalent 

 consequence, and from every consequence iis equivalent 

 antecedent, and bringing vital as well as physical phenomena 

 under the dominion of that law of causal connection which, as 

 far as the human understanding has yet pierced, asserts itself 

 everywhere in nature. Long in advance of all definite experi- 

 ment upon the subject, the constancy and indestructibility of 

 matter had been affirmed, and all subsequent experience 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 transmuted air, 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 

 till unlocked by the nerves, and then resulting in muscular con- 

 tractions. The speed at which messages fly to and fro along the 

 nerves was determined, and found, not as had been previously 

 supposed, equal to that of light or electricity, but less than the 

 speed of a flying eagle." 



" Following this work of the physicist came the conquests of 

 the comparative anatomist and physiologist revealing the struc- 

 ture of every animal, and the function of every organ, in the 

 whole biological series, from the lowest zoophyte up to man." 



