260 
The monkey was inoculated on the skin of the abdomen with vaccine virus 
No. 148 on the twenty-third day after the first inoculation. This second vaccina- 
tion was followed by no reaction. 
SUMMARY. 
(1) Objective description of the specific skin lesion based upon the 
appearances in twenty-eight monkeys.—After 48 hours the lesion appears 
as a simple scratch with more or less opacity and elevation, not extending 
over 2 millimeters from the line of inoculation. 
After 72 hours the elevation may become less in extent and take on a 
pink color, or it may remain as before. 
After 96 hours the elevation becomes more marked and more sharply 
circumscribed, and may begin to show translucence about the crust which 
forms along the line of inoculation. 
After 5 days the zone of translucence about the crust is more evident 
and contains fluid, which forms a vesicular ring about the crust. The 
contents of this vesicle is a clear fluid. The vesicular ring is bordered 
externally by a zone of red, which fades peripherally. The whole lesion— 
i. e., crust, vesicle, and areola—forms a rounded elevation, which flows 
into the general skin surface without a sharp line of demarcation. 
After 6 days the various parts of the lesion remain the same as on the 
fifth day, but there is an increase in the total width. The vesicle ring 
spreads peripherally, and coincident with this the crust encroaches upon 
the inner side of the vesicle ring. ‘The inner part of the vesicle ring may 
present an opaque appearance at this stage. ‘The crust may be more or 
less depressed in such a manner that the vesicular ring forms a rampart 
about it. 
After 7 days the conditions remain the same, there being more or less 
spreading of the whole lesion, accompanied by an increase in the extent 
of the central crust. At this stage, the outer edge of the vesicular ring 
may present an abrupt declivity, so that the whole lesion forms a flat- 
topped plateau. The skin proper is thickened and hard, and a subcu- 
taneous oedema is apparent beneath the lesion. 
After 8 days the lateral extension of the lesion has ceased and the 
central crust has encroached upon the vesicular ring. The subcutaneous 
cedema noted after 7 days is now more noticeable, often presenting itself 
as a broad indurated base. 
From this time on the healing of the lesion proceeds rapidly. The 
central crust finally occupies all the space previously held by the vesicular 
ring, being bordered by the pink epithelium which is growing inward 
from the normal skin. This newly formed epithelium slowly spreads 
beneath the crust, and finally the latter falls off, leaving a pink and shin- 
ing scar. 
The lateral excursions of the process outward from the line of inocula- 
tion amount to from 6 to 8 millimeters, measuring from the center of the 
crust to the outer edge of the vesicular ring. After 5 days, when the 
