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lesion in the epidermis and to an invasion of the blood vessels by the 
organism. 
The process in the corium and in the subcutaneous tissue beneath the 
lesion does not present such definite areas of necrosis as will be described 
in the variolous lesions. This may be due to the fact that the vaccine 
lymph was glycerinated, and so was free from pyogenic organisms, while 
the variola virus was untreated and contained streptococci and other 
pathogenic bacteria. It is to be noted that beneath the vaccine lesions 
capillaries invaded by cytoryctes were only found near to the infected 
epidermis while, as will be shown, in variolation the specific process ex- 
tends deeply into the subcutaneous tissue. ' 
(3) Constitutional reaction—The general condition of the animal 
does not seem much disturbed. There may be some anorexia about the 
sixth day, but it can not be said to be constant or marked. 
(4) The temperature reaction is not very definite, although there is 
to be derived from it evidence of a constitutional reaction. ‘The most 
common reaction is a slight rise on the sixth and ninth days of the 
disease. This fever rarely exceeds 40° C. The temperature reaction is 
not nearly so typical as in variola inoculata. 
(5) The lymph nodes.—With the development of a vaccine lesion on 
the belly of a monkey there is a reaction. of the axillary lymph nodes. 
This is shown by an enlargement, first noticeable on the fourth day (after 
3 day’s development of the lesion), which becomes more apparent on the 
succeeding days. On the sixth or seventh day the nodes may be 1 centi- 
meter in diameter and tender. With the regression of the lesion the 
nodes decrease in size but remain more firm than they are normally. 
The histology of the axillary lymph nodes of monkeys vaccinated on 
the abdomen presents the same picture as that seen in the variolated 
monkeys. Oedema of the sinuses and the presence of phagocytic endo- 
thelial cells, red blood corpuscles, and leucocytes, together with a small 
amount of fibrin, characterize the process in the nodes taken from animals 
during the active evolution of the vaccine lesion. 
(6) A general exanthem has never occurred in our vaccine monkeys 
(total 28). In some cases secondary lesions occur about the primary 
lesion (daughter pocks). ‘These run the same course as the primary 
lesions. Auto-inoculations are not uncommon, but in all instances which 
we have observed their occurrence was so obviously due to infection from 
the initial lesion by acts of the animal that the question of their being 
of the nature of an exanthem could not be raised. 
(7) No lesions were found in the internal organs. The bone marrow 
and testes were found free from the focal lesions which occur in these 
organs in variola vera in man. Cytoryctes variole was constantly found 
associated with the specific process in the skin at the site of inoculation. 
The question of the occurrence of the organism will be considered more 
in detail in a separate section of this report. 
