oe ae eee ee a et Sees! lle A | 
287 
sive healing of the process. The vesicle soon disappears and the polynuclear leu- 
cocyte infiltration of the whole field becomes less intense and eosinophiles appear. 
The epithelium grows inward under the crust and is joined by that which comes 
from the proliferation of cells of the hair sheaths. The blood vessels of the 
corium, send out prolongations, and the usual phenomena of repair dominate the 
picture. . 
The exanthem: Sections of lesions collected on the first day of the appearance 
of the exanthem show a vesicular cavity of variable size in the epidermis. This 
cavity is roofed by a layer of cornified epithelium and laterally and below is 
surrounded by thickened epithelium. The cells adjacent to the cavity show vary- 
ing degrees of degeneration. In every case the layer of the rete which forms the 
floor of the vesicle is wanting at one or more points, so that the cavity in the 
epidermis is in communication with the corium. The blood vessels and the lym- 
phatics of the corium beneath the lesion present marked changes. These are in 
part due to the migration of polynuclear leucocytes which is going on from the 
vessels into the corium, the vesicle, and the epithelium about it. Besides this 
purely exudative phenomenon the endothelial cells of the capillaries and of the 
lymphatics show marked swelling and some proliferation. The normal relation- 
ships of structure in the corium are much disturbed by this combination of exuda- 
tion, proliferation, and swelling. A careful search of such areas failed to show 
any cytoryctes, although they were numerous in the cells of the rete which formed 
the floor of the vesicle. 
Sections from the exanthem collected later in the evolution of the lesion show 
an increase in the size of the vesicular cavity, but no characters other than those 
found in the early lesions. 
The study of sections from the primary lesions and of the exanthem in MW. 
nemestrinus show variations in degree but not in kind from the picture seen in 
the corresponding lesions in the Philippine monkey. The reaction in the sub- 
cutaneous tissue and in the corium is more marked and edema plays a more im- 
portant rdle. The vesicle is not so well developed, but is similar in all funda- 
mental characteristics to that in M. cynomologus. 
Axillary lymph nodes: The sinuses are dilated, sometimes to a high degree. 
The cell content of the sinuses shows various deviations from the normal. The 
most prominent character is an increase in the number of endothelial cells. 
These cells increase greatly in size, become free in the sinuses, and show marked 
phagocytic properties. In the nodes from monkeys killed on the sixth and eighth 
days of the disease the included cells are in part red blood corpuscles and in part 
polynuclear leucocytes. Later the polynuclear leucocytes are the common inclusion, 
though lymphoid and other cells may occasionally be found within the phago- 
cytes. Besides the endothelial phagocytic cells, red blood corpuscles, and poly- 
morphonuclear leucocytes are found in considerable numbers free in the sinuses. 
The latter cells predominate in the nodes from animals killed on the ninth day 
of the disease and later. Eosinophile cells are frequently encountered, but do not 
as a rule occur in such numbers as do the polymorphonuclear leucocytes. 
The follicles show many phagocytic endothelial cells, singly or in small groups, 
scattered through their substance. In nodes from animals killed on the eighth 
day of the disease, small areas of hemorrhage were frequently found. In these 
areas red blood corpuscles were present in the follicular tissue about a small 
capillary, many of them having been taken up by phagocytes. In nodes collected 
later in the disease large phagocytic endothelial cells were demonstrable, whose 
whole cell body was crowded with red blood corpuscles in various stages of dis- 
solution. In one node, collected on the eighth day of the disease, masses of 
eosinophile leucocytes were present in the follicles and in the sinuses. These cells 
differed from the usual eosinophile cells in that the granules were elongated. 
