REGENERATION OF LOST PARTS IN ANIMALS. 49 
capable of starting the development of another claw, not a 
rudiment visible to the eye indeed, but a residual particle 
of specialised germ-plasm, lying there awaiting a possible 
awakening stimulus. 
Or perhaps we may conceive that in certain animals and 
parts of animals, the cells which once took part in growth, 
but have become, as it were, stereotyped in certain forms, 
still retain a residual power of doing what was done once 
before, and that when a wound is made, there comes about 
a re-arrangement and re-adjustment of the molecular con- 
stitution of the implicated cells, who thereupon set about 
their old task of growth, not always, however, able to 
accomplish it perfectly, and sometimes so affected by the 
novel stimuli that they do it hurriedly in a rough and 
ready fashion, or in a wrong way altogether. 
But these matters are too high for us, we cannot under- 
stand them. Therefore, I have contented myself in this 
paper with arguing for Léssona’s law that regeneration is, 
in its expression, an adaptive phenomenon, tending to occur 
in those animals and in those parts of animals which are in 
natural conditions most liable to loss, always provided that 
the part lost be of real importance, and that the injury be 
not in itself fatal. All of which comes to this, that the 
distribution of regenerative capacity is to be accounted for 
on the theory of Natural Selection.* 
* This paper was read before the appearance of Prof. Morgan’s treatise on 
‘Regeneration’ (1901), which supplies the serious student with a most 
instructive balance-sheet of facts and opinions, 
ANTS. 
By J. G. GoopcuILD, of the Geological Survey, F.G.S., F.Z.S., 
Custodian of the Collections of Scottish Geology and 
Mineralogy in the Edinburgh Museum of Science and 
Art, Past President. 
(Read 4th April 1901.) 
Ir has probably happened to most people who have been 
sitting on a sunny bank in the warmer months of the year, that 
VOL. II. 
