OBJECTIONS TO THE THEORY 841 



This conclusion, which implies great breaks or discon- 

 tinuity in the series, appears to me improbable in the 

 highest degree. 



Every one who believes in slow and gradual evolu- 

 tion will of course admit that specific changes may have 

 been as abrupt and as great as any single variation which 

 we meet with under nature, or even under domestication. 

 But as species are more variable when domesticated or 

 cultivated than under their natural conditions, it is not 

 probable that such great and abrupt variations have often 

 occurred under nature as are known occasionally to arise 

 under domestication. Of these latter variations several 

 may be attributed to reversion; and the characters which 

 thus reappear were, it is probable, in many cases at 

 first gained in a gradual manner. A still greater num- 

 ber must be called monstrosities, such as six-fingered 

 men, porcupine men, Ancon sheep, Niata cattle, etc. ; 

 and as they are widely different in character from nat- 

 ural species, they throw very little light on our subject. 

 Excluding such cases of abrupt variations, the few which 

 remain would at best constitute, if found in a state of 

 nature, doubtful species, closely related to their parental 

 types. 



My reasons for doubting whether natural species have 

 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 fol- 

 lows. According to our experience, abrupt and strongly 

 marked variations occur in our domesticated productions, 

 singly and at rather long intervals of time. If such oc- 

 curred under nature, they would be liable, as formerly 

 explained, to be lost by accidental causes of destruction 



