THE CLOSING OF WOUNDS IN THE LARVAL NECTURUS. 
BY 
ALBERT C. EYCLESHYMER. 
From the Anatomical Laboratory of St. Lowis University. 
WITH 10 FIGURES. 
While studying the normal development of Necturus, the writer fre- 
quently noted that accidental wounds closed with astonishing rapidity. 
These observations gave a starting point for the following experimental 
study. 
The larve selected for the experiments were about 20-21 mm. in 
length.. This stage was chosen because at this time the dermis is deeply 
pigmented over the dorsal surface and casual observations had shown 
that over this dark background certain light spots, presumably epidermal 
structures, moved toward the margin of the wounds. JHach larva was 
placed in a solid watch glass containing a bed of cotton, in the meshes of 
which it soon became entangled and was thus held in given position. A 
small piece of skin about 2 mm. long and 1 mm. wide was then cut from 
the mid-dorsal region. In most of the experiments only the skin and 
subcutaneous tissues above the spinal cord were excised, yet in some, the 
spinal cord was more or less injured. 
As soon as the excisions were made the larve were placed in separate 
dishes and examined either at short intervals, or continuously under the 
Zeiss binocular microscope with the No. a, objective and the No. 4 
oculars. Under this high magnification, one could readily follow the 
moyements of individual cells either remote from or at the margin of the 
cut. By this means it was found that the deeply pigmented dermal 
chromatophores remained practically stationary while large irregularly 
scattered epidermal cells moved toward the margins of the wound. By 
following the movements of these cells which the study of sections 
showed to be the unicellular gland cells, it was possible to determine the 
rate of movement of the epidermis over the dermis. 
Since the rate of movement was practically the same in all the experi- 
ments, it will suffice to illustrate the process by a single series of diagrams 
which were taken at intervals from a single larva. On July 21, 9 a. m., 
AMERICAN JOURNAL OF ANATOMY.—VOL. VII. 
