102 INHERITANCE 



produced from a fertilised egg. Inasmuch as these 

 two forms are not only similar to each other, but 

 similar also to their parents, it follows that a 

 Theory of Inheritance, to be of any real value, 

 must apply equally to sexual and asexual pro- 

 cesses of reproduction. I lay stress on this point 

 as it is one which appears to me to have 

 been very frequently overlooked, especially of late 

 years. 



The power of repairing mutilation, that is 

 possessed in so marked a degree by many animals, 

 is another phenomenon of which account must be 

 taken in any Theory as to the real nature and 

 mode of action of Inheritance. A Hydra may be 

 cut into many pieces, and each piece will regenerate 

 the missing portions and give rise to a perfect 

 animal. One or more of the arms of a starfish 

 may be removed, the whole of the viscera of an 

 Antedon may be turned out, the leg of a crab or 

 the limb or tail of a newt may be cut off, and the 

 loss will in each case be made good. Spallanzani 

 cut off the tail of a salamander six times in suc- 

 cession, and Bonnet eight times ; while the eye- 

 bearing tentacle of a snail has been removed 

 twenty times ; and yet after each mutilation the 

 missing organ has been reproduced. In the more 

 highly organised animals, such as birds and 

 mammals, this power of repairing mutilation is 

 much restricted : removal of parts of the epidermis 

 is, however, readily made good ; while such 

 operations as skin-grafting, and transfusion of 

 blood from one animal to another, show that 



