REGENERATION OF LOST PARTS IN ANIMALS. 39 
of Bordage, that in cock-fights similar injuries were frequent, 
and were often followed by most striking regeneration, In 
one case the premaxille and part of the mandible were torn 
off—a large fraction of the entire beak—yet both bones 
and horny coverings were regenerated, Now, cock-fighting, 
though elaborated by men of more or less evil device, is a 
natural phenomenon, and, in connection with regeneration 
problems, of much more biological importance than the 
careless might suppose. When we remember that male 
storks also fight furiously, sometimes fatally, the difficulty 
of the stork’s bill seems, as Weismann says, almost to 
become an exception proving the rule. 
Everyone is familiar with the fact that a lizard seized by 
its tail or struck on the tail may relinquish possession of 
that appendage and thus save its life. Natural history 
curiosity-books describe the muscular wrigglings of the 
detached member. Now, since the lizard’s tail is a part that 
would be naturally enough seized by a cautious enemy, that 
there should be organic provision for its replacement is not 
surprising. The fact that there is in some cases a structural 
peculiarity in the vertebree which renders breakage easy, 
corroborates the interpretation. The frequent exuberance 
of the organic provision for regrowth was illustrated by a 
lizard which I had for some time in my possession, whose 
tail from a certain point was double. So far good, but 
what of those cases where there is in lizards’ tails either no 
regeneration after loss or only a very incomplete one? 
Part of the answer has, I think, been given by Werner, who 
has devoted much attention to lizards’ tails, for he points 
out that the regeneration is absent or very incomplete in 
those whose tails are differentiated as prehensile, or as 
defensive organs. It seems plain that a tail which is 
known to strike, or a tail coiled on a branch, would be much 
less likely to be seized than the ordinary wagging and 
partially locomotor tail of other lizards. 
Another difficult case which Weismann discusses is that 
of the eye of the newt (Zviton), which may be regenerated, 
as Bonnet and Blumenbach showed, after very serious injury. 
We now know that if the lens alone be carefully taken out, 
it will be replaced—a fact to which I must afterwards refer. 
