1930 ] 
Development of Dermatobia hominis 
333 
of these is an intense itching of the skin of the area sur- 
rounding a lesion. This may be due to an infiltration of 
the tissues with the faeces of the larva and other fluids 
present in the lesions causing a slight cellulitis. This itch- 
ing was not constant but occurred at frequent intervals, 
and is induced by even very slight friction in the vicinity of 
the lesion. The second sensation is a very irritating prick- 
ing which takes place in the lesion. This is probably caused 
by the rasping of the cutaneous spines or hooks on the larva 
during any movement of the latter. The third sensation is 
a sharp, stinging pain, which is believed to be produced by 
the tearing of the tissues by the oral hooks of the larva 
when it becomes necessary to use the hooks in order to 
excite the flow of serum or blood to serve as food. 
October 29. Nos. 3 and 6 are now much more swollen 
than are the other four lesions which are located in areas 
of more adipose and muscular tissues. The four located in 
more favorable situations are but little swollen on the out- 
side, but can be felt as hard nodules, each as large as a 
good-sized marble and seeming to extend into the sub- 
cutaneous tissues. During the past three days there has 
been less of the pricking sensation occurring. This may 
be due to the lesions becoming walled off so that each larva 
is to some extent encapsulated. Or, again, it may be due 
to wearing bandages over the lesions. When the latter 
were exposed to the air the exudate soon dried and formed 
small scabs that at times seemed to seal over the small 
openings of the lesions, and it is quite plausible to believe 
that in order to burst through these scabs some struggles 
were required on the part of the larvse when it was 
necessary for them to take air or discharge fecal matter. 
With the lesions bandaged the exudate is being continually 
absorbed and the holes left open and moist around the 
edge. A quite pronounced vesicular eruption has now ap- 
peared on both hands and wrists and on my right leg. 
This is accompanied by an intense itching and a slight 
oozing of serum from the vesicles. 
October 31. During yesterday and today there have been 
several attacks of excruciating pain experienced from Nos. 
3 and 4. This pain was possibly a nerve irritation caused 
by the oral hooks of the larvae tearing the tissues. These 
