246 ELIOT R. CLARK AND ELEANOR LINTON CLARK 
while those outside the area continued to send out fine processes 
and to grow in a normal manner, but in no case do we find any 
evidence of endothelial proliferation to form wandering cells. 
In a number of cases, hemorrhages occurred from blood capil- 
laries located near the croton oil. The extravasated red blood 
corpuscles were taken up by the lymphatic vessels, as well as by 
leucocytes of both the pigmented and clear varieties. The 
method by which the occasional extruded red blood-cell found 
in the normal tail is taken up has been described by one of the 
authors (EK. R. Clark, 709). In this case the process was the 
same, but on a much larger scale. Instead of one sprout growing 
toward a single blood-cell, a number of processes appeared on 
both sides of the lymphatic and, by means of these, several red 
blood corpuscles were picked up and simultaneously taken into 
the lumen of the vessel, where they were seen to move along 
the lymph capillary to the main longitudinal lymphatic. After 
two or three days, such an area would be almost clear of blood- 
cells, and the majority of these would have been salvaged by the 
activity of the lymphatics. 
In a number of larvae an edema developed in the injured 
region. This usually occurred soon after the extrusion of the 
globule, although it was sometimes noted on the following day. 
The edema may be demonstrated by measuring the thickness 
of the tail by means of the fine-adjustment screw. The appear- 
ance of the tail is altered in such areas; the region becomes 
clearer, the connective-tissue cells more widely separated, and 
all the leucocytes, including the pigmented ones, round up into 
spheres. The lymphatic sprouts of the area become markedly 
distended at the tip. This enlargement is evidently due to an 
increase in the fluid content of the vessel, for the endothelium 
is represented merely by a thin line.. This differs from the 
enlargement of the lymphatic tips which occurs soon after the 
introduction of the croton oil and which is due to a swelling of 
the endothelial cells proper. Figure 15 shows successsive records 
of a lymphatic sprout in an inflammation area which has become 
edematous after the extrusion of the globule of croton oil. Com- 
parison of the different drawings with the measurements of this 
