C. M. Wenyon 
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These persisted for upwards of a year, and in them I was able to 
demonstrate the typical parasite. As a rule however the incubation 
period is longer and the sore may make its first appearance many 
months after a person has left the infected district. It is probable that 
the time elapsing between inoculation and the appearance of a noticeable 
sore is very variable and may depend on several factors, such as a 
person’s natural resistance to the disease, the state of health at the time 
of inoculation, or the virulence and numbers of the parasite inoculated. 
From the first moment of inoculation the parasities must have been 
multiplying in the skin at the point of infection, and it is otily when 
their number is sufficiently great that a visible change is produced on 
the surface. 
From experimental inoculations more precise data can be obtained, 
though even here one must exercise caution in drawing conclusions, as 
the natural manner of infection may produce a sore more slowly or more 
quickly than by the inoculation of parasites from man to man. I 
inoculated a European lady on the left forearm with the juice squeezed 
from a sore on the arm of her husband. By microscopical examination, 
the juice was shown to contain numerous parasites. The inoculation 
was done by placing the juice on the skin and scarifying with a sharp 
instrument as in vaccination against smallpox. The wound caused by 
the scarification completely healed, though the mark or scar persisted 
and no definite development took place for some time. At the end of 
seven weeks from the time of inoculation, there was present at this spot 
a typical sore in the form of a small papule of about five millimetres in 
diameter. Later there appeared on the other arm two small sores which 
were probably the result of a natural infection if we remember Dr 
Saati’s experiments. Though in this case the mark of the wound caused 
by the inoculation never completely disappeared, this is not usually the 
case as will be seen from the following interesting information on the 
subject of inoculation given me by Dr Saati of Mousul, who has practised 
protective inoculation for some time. He has been in the habit of 
inoculating people with the juice of the sore as in vaccination against 
smallpox, on the outer side of the leg. The sore thus produced heals 
quickly and finally all trace of the inoculation disappears. At the end 
of two months, or occasionally it may be three or four, there appears at 
the point inoculated a minute red papule which increases in size till it 
assumes the form of a typical sore. Dr Saati has inoculated about 
three dozen cases, and in the greater number of these the incubation 
period has been about two months. It is important to note that the 
