150 S. R. DETWILER 
is not always possible to remove the entire rudiment in a typical 
limb extirpation. Owing to its equipotentiality, certain unre- 
moved cells then may be sufficient in number to regenerate the 
appendage after the bulk of the rudiment has been removed. 
This regeneration has been shown to be greater in wounds which 
have not been covered (Harrison, 715). In the series ASI, in 
which the limb rudiment was removed the distance of only one 
segment posterior to the normal position, the wounds were not 
covered, the denuded area being so small that it could not easily 
be covered. From the anterior border of these uncovered wounds 
there occurred twelve cases in twenty-five which showed signs 
of regeneration. These consisted of small nodules of cells which 
began to project from the body about four days after the oper- 
ation. These regenerating nodules, however, were very close 
to the transplanted rudiment, being separated only by the 
distance of one segment. They gradually decreased in size, 
however, until the eighth day after the operation they entirely 
disappeared and in no case did regeneration occur. 
In the series AS2, where the limb rudiment was removed the 
distance of two segments, only five of the wounds were uncovered. 
Here ten cases in twenty-one began to regenerate the limb from 
small nodules of cells at the anterior border of the wound, as in 
the series ASI. These nodules of regenerating cells also began 
to appear on the surface of the body about four days after the 
operation. Some of these nodules began to increase in size, So 
that on the fifth and sixth days regeneration appeared very 
probable; however, they soon began to decrease in size, and by 
the eleventh day all signs of regeneration had entirely disap- 
peared. Although the initial regenerating nodules in this series 
were about as large as those in the series ASI, their total dis- 
appearance did not occur until three days after total disappear- 
ance of those in the series AS1. 
In the series AS3, in which the limbs were removed by the 
distance of three segments, the wounds were cleaned and covered. 
In twenty-three experiments there occurred ten cases inwhich ° 
regenerating nodules appeared. Some of these subsided about 
the fifth and sixth days, while others had developed so that by 
