No. 3.] 



THE REGENERATION OF TISSUE. 



of the fin is derived from the major component. The differ- 

 ences in the mesodermal pigment cells are at times very strik- 

 ing, and in all such cases the pigment cells are like those in the 

 tissues from which they immediately arise ; but while in many 



A (.April 25). 



B (May 2). 



cases they furnish a safe criterion, in others the difference 

 cannot be made out with certainty. On the other hand, the 

 differences in the muscle tissue of the core can always be seen. 

 The explanation of the result, viz., that the new tail is in 

 most cases (in forty-seven cases out of sixty) like the minor 

 component, is that in nearly all of these operations too large 

 a piece of the grafted tail has been left. It has contained the 



