12 
Doctor Goldberger, further, removed from some straw siftings five 
minute mites, and, placing them in a clean watch crystal, applied the 
crystal to the axilla of another volunteer. At the end of about sixteen 
hours following this application five of the characteristic lesions ap- 
peared on the area to which the mites had been applied. (See fig. 
8, from drawing by F. H. Wilder.) 
INFLUENCES CONTROLLING THE EXCESSIVE ABUNDANCE OF 
PEDICULOIDES. 
It will be noticed that Doctors Goldberger and Schamberg made no 
attempt to discover the underlying causes for the enormous numbers 
of these mites inhabiting the mattresses involved in their investiga- 
tions, that problem 
coming properly 
within the realm of 
entomology. When 
the writer took up 
this subject with the 
view of finding out 
the causes for such an 
abundance of these 
mites, Doctors Gold- 
berger and Schamberg 
very kindly placed at 
his disposal every- 
thing in their posses- 
sion relating to this 
epidemic, including 
the mattress which 
Doctor Goldberger 
had himself used in 
Fig. 8.—Lesions caused by bites of the mite Pediculoides ventricosus. experiments with this 
About natural size. 
mite, carried out by 
him at the Hygienic Laboratory in Washington. Doctor Schamberg 
was equally kind in placing at his service all of the material, notes, 
and photographs in his possession. 
Almost at the commencement of the investigation, Dr. William 
Royal Stokes, of the Maryland state board of health, informed the 
writer that a similar but less extensive epidemic had shortly before 
been noted in Baltimore. This he kindly described as follows: 
The matter was brought to my attention by several persons, who came to the head 
of the department and complained of the skin eruption described. They stated 
that a number of people in a suburban hotel were similarly affected, but I do not 
remember the number at this late date. These persons volunteered the information 
that they had all been sleeping on some new straw mattresses, and that all of the 
persons similarly affected had used these mattresses. 
[Cir. 118] 
