No. 6.] LIABILITY TO INJURY. 299 



anterior abdominal appendages of the male still capable of 

 regeneration, we do not know with certainty that the parts are 

 degenerate. The question is further complicated by the amount 

 of food material that is brought to the part of the body from 

 which the appendage springs. If the amount is small, we can 

 readily imagine that the regeneration may be retarded, or not 

 even started, although the cells might be potentially capable of 

 regenerating the missing part. It is not improbable that the 

 smaller ' reduced ' appendages would be most likely to suffer 

 in this respect. 



There is still another factor that must be taken into account, 

 viz., the place at which the appendage is cut off, for it is prob- 

 able that, while an appendage may regenerate at one level, it 

 may not be able to do so at another. Perhaps, for instance, 

 had the abdominal appendages been cut off nearer to the body, 

 a larger or smaller percentage would have regenerated. 



In regard, however, to the problem of the frequency of injury 

 of a part and its capability to regenerate, the preceding results, 

 I think, speak with sufficient clearness. No such relation is 

 found to exist. The advocates of such a view overlook a very 

 vital part of the problem. If, for instance, it were found, as 

 the result of a large number of observations, that those animals 

 or parts of animals that were most subject to injury had most 

 highly developed the power to regenerate lost parts, it would 

 by no means follow, as Weismann and other Darwinians claim, 

 that this result must have come about by what they call a 

 process of natural selection. They overlook the possibility that 

 unless these animals had from the beginning the power to 

 regenerate they could not continue to live under the adverse 

 circumstance. The animal would be then either entirely 

 destroyed or else confined to other locations where the danger 

 did not exist. Many persons confuse this statement with the 

 theory of natural selection, but the two views are as wide as 

 the poles apart. 



We need not, perhaps, be greatly concerned with the argu- 

 ment that attempts to make plausible a connection between 

 accidental injuries and the power of a part to regenerate, for 

 there are known already a number of remarkable cases of 



