506 Charles Zeleny 
tions of the four legs, and an equal number of successive reproduc- 
tions of the tail at the same time. In one of these salamanders 
the reproduced bones of the legs and tail amounted in these three 
months to 687. This number of reproductions seemed not to 
have lessened in any considerable degree the regenerating power, 
as the last was obtained in the same number of days as the former. 
As this power manifests itself from April to September, it is very 
probable that, by beginning these sections in April and con- 
tinuing them during all that time, one might obtain in these six 
months twelve reproductions both of the legs and tail.” 
1-b The second group of statements showing a decrease can- 
_ not be relied upon in the absence of proof that the whole physiolog- 
ical activity was not declining as a result of causes quite apart from 
removal. 
1-c ‘The third group includes two instances of special interest. 
Vanlair ( 94) finds in the sciatic nerve of the dog that the second 
regeneration is more rapid than the first, occurring in seven and a 
half months as opposed to ten months for the first regeneration. 
He says “Une autre remarque faite sur un de mes chiens mérite égale- 
ment de fixer l’attention. Ayant pratiqué sur un sciatique déja 
régénéré ne seconde section a I centimétre au-dessus du premier 
niveau, j’ai pu constater que le deuxieme restauration ’accom- 
plissait en un temps sensiblement plus court que la premiere. 
Alors que celle-ci avait exigé un délai de dix mois, Pautre n’a 
demandé que sept mois et demi. Il semble, d’aprés cela, qu’un 
prem er effort de régénération rende plus facile le travail néces- 
saire a une restauration ultérieure.”’ 
The subcutaneous tumor known as a keloid growth is said to 
regenerate more rapidly the more often it is removed. 
2 ‘The data showing an effect upon the character of the regener- 
ation apart from rate may be grouped in the same way: (a) cases 
in which no change is noticed, (b) cases in which a change is shown. 
2-a ‘The general statement is made that successive removal 
has no effect upon the character of regeneration. (Spallanzani 
(1769) and others.) 
2-b On the other hand there are some cases on record showing 
a change in character with successive removal. Thus Driesch 
