win's theory of ''the Origin of Species b}' 

 Natural Selection" have always refused 

 to give a tangible definition of the word 

 ''species," and, as a result, the real diffi- 

 culty turns upon that point. What is a 

 species ? Linnaeus said : "There are as 

 many species as an infinite Being created 

 at the beginning," a statement which is 

 a confession of faith, and not a scientific 

 definition. We must remember, of 

 ■course, that Linnaeus died as long ago as 

 1778. The truth is that all the various 

 tests for species have proved faulty, that 

 of the fertility of hybrids having little 

 more value than many of the other so- 

 called "tests." In classification, the 

 word "species" means the lowest subdi- 

 vision tO' which a name is usually applied, 

 .and to aid the zoologist's or botanist's 

 memory, some system of cliassification is, 

 I need not say, an absolute necessity. 



According to the view of the anti-evo- 

 lutionists, most of whom are not scientific 

 men, descendants of a common ancestor 

 must belong to the same species. Never- 

 theless, the late Mr. Romanes has shown 

 that the rabbits of Porto Santo, an island 

 in the Atlantic, about twenty-five miles 

 from Madeira, descended from the Euro- 

 pean stock of nearly 500 years ago, will 

 no longer breed with their continental 

 cousins. 



When we remember that some wild 

 animals will not breed in captivity, the 

 idea of sterility as a test of species seems 

 utterly unscientific. I venture to- say that 

 there can be no accurate definition of 

 species in terms of physiology, for every 

 individual has its peculiarities, chemical 

 as well as physical, and the real difficulty 

 is to decide when these peculiarities are 

 important enough to make it useful to 

 give a precise name to their possessors. 

 Assume for a moment that a species is a 

 grou]) of individuals agreeing in essential 

 characters which remain constant from 

 one generation to another. But what arc 

 essential characters and how much con- 

 stancy is demonstrated? Upon these 

 points no two biologists arc likely to 

 agree. For example, taking the birds of 

 Germany, Bech stein says there are 367 

 species; Brehm says there arc 900. / - 



cording to Reichenbach there are 379, 

 and Meyer and Wolf tell us there are 406. 



The idea of a species is based upon 

 structural resemblances between individ- 

 uals, and the degree of importance at- 

 tached to these depends upon the mind of 

 the particular observer. 



There arc two reasons why nobody has 

 seen one species turn into another. The 

 first is that until the word "species" is 

 satisfactorily defined, instances of the 

 evolution of new forms cannot be sup- 

 plied. Secondly, as nobody lives much 

 beyond a hundred years at the most — a 

 mere moment in Nature — our ability to 

 witness marked changes in animals or 

 plants is extremely limited. Minor 

 changes, of course, are frequently no- 

 ticed. I ask the reader to remember, 

 however, that the flower-garden and the 

 farm-yard are in an artificial -condition. 

 Natural Selection having ceased. For 

 instance, the duck which has defective 

 wmgs when hatched has as good a chance 

 of surviving as the duck with powerful 

 wings. 



Who are the opponents of the doctrine 

 of Evolution? In the scientific world 

 they are difficult to find. Professor Vir- 

 chow, of Berlin, the distinguished pathol- 

 ogist must, I think, be classed as one, al- 

 though his verdict is really "not proven.'' 

 Professor Haeckel, however, has pointed 

 out that the opinion of a pathologist, no 

 matter how eminent, upon the subject of 

 evolution cannot carry much weight. 



Until recently we had with us two men 

 of science whose opposition to some por- 

 tion of the doctrine of evolution was of 

 importance. These men were Sir W^ill- 

 iam Dawson, the Canadian geologist, and 

 Mr. Mivart, the English anatomist. Both 

 of these gentlemen have died within the 

 past two years. 



Having now written a brief outline of 

 the doctrme of Evolution, I believe that I 

 cannot do better than conclude this very 

 imperfect sketch with a quotation from 

 the inunortal Shakesjx^are : 



''The truth can iievor be conlirnuMl enou.ch. 

 Tlioutih doubts (lid over sleep." 



Lawrence Irwell. 



210 



