224 MISCELLANEOUS OBJECTIONS TO THE 



changed as abruptly as have occasionally domestic races, 

 and for entirely disbelieving that they have changed in the 

 wonderful manner indicated by Mr. Mivart, are as follows : 

 According to our experience, abrupt and strongly marked 

 variations occur in our domesticated productions, singly and 

 at rather long intervals of time. If such occurred under 

 nature, they would be liable, as formerly explained, to be 

 lost by accidental causes of destruction and by subsequent 

 intercrossing ; and so it is known to be under domestication, 

 unless abrupt variations of this kind are specially preserved 

 and separated by the care of man. Hence, in order that a 

 new species should suddenly appear in the manner supposed 

 by Mr. Mivart, it is almost necessary to believe, in opposi- 

 tion to all analogy, that several wonderfully changed indi- 

 viduals appeared simultaneously within the same district. 

 This difficulty, as in the case of unconscious selection by 

 man, is avoided on the theory of gradual evolution, through 

 the preservation of a large number of individuals, which 

 varied more or less in any favorable direction, and of the 

 destruction of a large number which varied in an opposite 

 manner. 



That many species have been evolved in an extremely 

 gradual manner, there can hardly be a doubt. The species 

 and even the genera of many large natural families are so 

 closely allied together that it is difficult to distinguish not 

 a few of them. On every continent, in proceeding from 

 north to south, from lowland to upland, etc., we meet with 

 a host of closely related or representative species ; as we 

 likewise do on certain distinct continents, which we have 

 reason to believe were formerly connected. But in making 

 these and the following remarks, I am compelled to allude 

 to subjects hereafter to be discussed. Look at the many 

 outlying islands round a continent, and see how many of 

 their inhabitants can be raised only to the rank of doubtful 

 species. So it is if we look to past times, and compare the 

 species which have just passed away with those still living 

 within the same areas ; or if we compare the fossil species 

 embedded in the sub-stages of the same geological forma- 

 tion. It is indeed manifest that multitudes of species 

 are related in the closest manner to other species that still 

 exist, or have lately existed ; and it will hardly be main- 

 tained that such species have been developed in an abrupt 

 or sudden manner. Nor should it be forgotten, when we 

 look to the special parts of allied species, instead of to dis« 



