353 
points along the scratches. One of these elevations was excised for histological 
study. Six days after inoculation there were small crusts situated upon the 
remaining scratches. These crusts were used to inoculate the corneas of rabbit 
No. 4. Nine days after inoculation, three small papules 2 mm. in diameter were 
present in the vicinity of the inoculation scratches. One such papule was excised 
for histological study. 
About a week subsequent to the last observation the monkey was inoculated 
with lymph from a case of variola in man and typical variola lesions developed. 
Stained paraffin sections of the skin excised four days after inoculation show 
the epidermis thickened over a small area, which is surmounted by a minute 
crust. There is no destructive process, only such a condition as might occur in 
the repair of an ordinary scratch. The papule excised nine days after inocula- 
tion shows a loss of epidermis over a minute area which is covered by a very 
delicate crust. (Such lesions were later found quite frequently in instances where 
the animal’s belly was shaved and were regarded as minute abrasions from 
scratching.) 
Rabbit No. 2.—The eyes were anesthetized with two per cent cocaine solution 
and the exudate from the human skin lesions rubbed into shallow incisions made 
upon the cornea. The corneas appeared smooth after twenty-four hours and, as 
no process could be detected in the daily observations for a week following the 
inoculation, the animal was not killed. 
Rabbit No. 3.—Both corneas were inoculated with the same exudate and in a 
similar manner as in rabbit No. 2. The corneas in this case healed rapidly and 
no process developed subsequently. Animal not killed. 
Rabbit No. 4.—Both corneas were inoculated with the crusts obtained from the 
inoculation of Monkey No. 1. The corneas became nearly smooth in from twenty- 
four to forty-eight hours. The animal was killed three days after inoculation. 
In sections of the cornea there appeared a ‘slight defect in the epithelium at the 
point inoculated, but no pathological process beyond that which might follow an 
ordinary injury was present. 
A number of cases subsequently appearing among the prisoners were 
seen at what was evidently an earlier stage in the development of the 
eruption. ‘These presented full hemispherical or oval vesicles which were 
easily ruptured and which contained clear fluid. Certain other cases seen 
with these presented lesions with a central crust surrounded by a 
vesicular zone containing either cloudy fluid, or whitish semi-fluid pus. 
Exudate was collected from both sorts of lesions and used to inoculate 
two monkeys. 
Monkey No. 5.—The belly was shaved and the clear vesicle contents mentioned 
in the text was rubbed gently into superficial incisions made at intervals upon 
this area of the skin. 
Another portion of the clear fluid was blown into the nostril of the monkey. 
This animal developed no skin lesion although under observations for several 
weeks. 
Monkey No. 6.—The skin of the belly was inoculated in a similar manner with 
the semi-fluid pus from the cases above mentioned. No lesions developed from 
this inoculation. 
The negative character of these inoculations indicates clearly that the 
disease is distinct from smallpox. The result was the same whether the 
pus or the clear fluid was used. The virus of smallpox, even when 
collected from the mildest cases, produces a typical process whether 
