320 The Closing of the Wounds in the Larval Necturus 
their movement toward the central part of the wound until the margins 
are now in contact. Since no new features are observed beyond those 
mentioned in the above paragraphs, a detailed description is unnecessary. 
It should, however, be stated that the movement of the dermal 
chromatophores is practically imperceptible. 
Twenty-four hours after the excision it was found, in all the larve 
excepting one, that the gland cells covering the wound have largely dis- 
appeared. The dermal chromatophores in some of the larve show a 
slight movement within the boundaries of the original cut, but on the 
whole there is little change in their position. July 26, 9 a. m., about 
120 hours after cutting, the gland cells are still absent. The dermal 
chromatophores have extended within the original margin of the wound 
until one-half the area of the wound is covered. August 8, the epidermal 
glands are present in numbers and the chromatophores cover the entire 
wound. 
The above study of the surface phenomena shows that in the brief 
interval of 90 minutes, the wound is completely closed when the 
temperature is about 18°C. 
This closure is brought about through the movement of the epidermis 
over the dermis. The cells which participate extend over a considerable 
area, as shown by the shifting position of the gland cells in regions re- 
mote from the cut surface. Some of the gland cells disappear during the 
time the margins of the epidermis are approximating and after the closing 
of the wound they undergo such rapid degeneration that 24 hours later 
there are very few present. 
After making as careful study of the surface phenomena as possible, 
this was supplemented by the study of serial sections, showing the vari- 
ous stages in the closing of the wounds. The larve were fixed in Zenker’s 
fluid and were then stained in toto with Czoker’s alum-cochineal, 
imbedded in paraffine, cut in serial sections and counter stained with 
Lyon blue. 
The earliest stage studied in sections, is from a 22 mm. embryo about 
5 minutes after cutting. In this particular larva, the epidermis, dermis 
and the greater portion of the spinal cord have been excised. As will 
be noted (Fig. 5) the wound has already filled with a coagulum made 
up of lymph, blood corpuscles and cellular fragments of the epidermis, 
dermis and spinal cord. The epidermis already shows a marked change 
in its character, in that it is much thickened around the margin of the 
wound. Often this margin is two or three times as thick as the normal. 
External to this thickened margin, the epidermis undergoes a gradual 
