REVIEWS. 
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that the window is open, he inspects it, and finds the mark of a dirty hand 
on the window-frame, and subsequently the impress of a hob-nailed boot 
outside on the gravel. Of course, he suspects that his plate has been 
stolen, and the hypothesis is that the owner of the dirty hand and hob- 
nailed boot is the thief. Undeterred by the counter-hypothesis of some 
kind friend, who suggests the possibility of the laws of nature having 
been “ suspended during the night,” and that there might have been “ some 
supernatural interference in the case,” he calls in the aid of the police, who 
track the burglar with the property on his person, and find that the marks 
correspond with his hands and boots. Under such circumstances, he 
thinks a jury would verify the hypothesis by convicting the prisoner. 
After showing that it was by such hypotheses that Newton and Laplace 
made their discoveries, and telling his readers that the value of the result 
of the hypothesis depends upon the pains taken in its verification, he pro- 
ceeds to say that it is on this inductive method of inquiry he means to 
consider the state of “ our present knowledge of the nature of the processes 
which have resulted in the present condition of organic nature.” 
The precise bearing of this anecdote to the point at issue is not given 
with the story itself, and we shall inquire how far it is applicable to the 
natural problem before us ; supplying what appear to us to be deficiencies, 
which might not occur to the <! working classes.”* 
The Story : — 
1. A gentleman misses his plate, and asks himself what has become 
of it. 
2. He finds evidence of a man having escaped from the windown 
3. From this evidence he concludes, or rather forms the hypothesis, that 
a burglar had stolen his plate, and has escaped from the window ; 
and determined to be guided by this hypothesis, he directs his 
investigations accordingly. 
4. On proceeding in his investigations, he finds the burglar with 
the property on his person, and has him convicted. 
The Moral : — 
1. A naturalist observes that certain groups called species are related 
together by structural and functional peculiarities ; and he asks 
himself how these species have originated. 
2. He finds that by artificial breeding or selection, man is able to form 
varieties and races ; and that similar influences to that exercised by 
man are all at work in nature. 
3. He conceives the idea of natural selection ; and assumes that 
“ species ” have thus originated. 
4. To he complete , the moral should conclude thus : — He investigates the 
operations of nature ; finds species formed by natural selection ; 
and thus realizing his hypothesis, he arrives at a satisfactory solu- 
tion of his problem. 
* At p. 137, the author specially refers to this anecdote as constituting a 
case analogous to the one at issue, namely, the causes of origin of new 
species. 
