428 Mr. Alfred Rtissel Wallace [Jan. 22, 



cation, variation, and survival of the fittest. Almost everv objection 

 that has been made to Darwinism assumes conditions of nature very 

 unlike those which actually exist, and which must, under the same 

 general laws of life, always have existed. 



Protective Colour and Mimicry. 



The phenomena of protective coloration and mimicry were \'ery 

 briefly alluded to, both because they are comparatively well known 

 and had formed the subject of previous lectures ; while they are 

 very easily explained on the general principles now set forth. The 

 explanation is tlie more easy and complete, l)ecause of all the 

 characters of living organisms, colour is that which varies most, is 

 most distinctive of the difl'erent species, and is almost universally 

 utilised for concealment, for warning, or for recognition. And 

 further, its useful results are clear and unmistakable, and have 

 never been attempted to be accounted for in detail by any other 

 theorv than that of the continuous selection of beneficial variations. 



TJie Dispersal of Seeds. 



The subject of the dispersal of seeds througli the agency of tlie 

 wind, or of carriage by birds or mammals in a variety of ways, and 

 often by most curious and varied arrangements, of hooks, spines, or 

 sticky exudations almost infinitely varied in tlie different species, was 

 also briefly treated, since they are all readily explicable by the laws 

 of variation and selection, while no other rational explanation of their 

 formation has ever been jriven. 



Cdnrlusion. 



In concluding, the lecturer called attention to a series of cases 

 which had shown us the actual working of natural selection at the 

 present time. He also explained that these cases were at present few 

 in number, first, because they had not been searched for ; but perhaps, 

 mainly, because they only occuj- on a large scale at rather long in- 

 tervals, when some great and rather rapid modification of the environ- 

 ment is taking place. 



In the following paragraph he endeavoured to summarise the 

 entire problem and its solution : " It is only by continually keeping 

 in our minds all the facts of nature which I have endeavoured, 

 however imperfectly, to set before you, that we can possibly realise 

 and comprehend the great problems presented by the 'World of 

 Life'— its persistence in ever-changing but unchecked development 

 throughout the geological ages, the exact adaptations of every species 

 to its actual environment both inorganic and organic, and the ex- 



