Distribution of Tropical Diseases in Africa. 473 
The action of the antidote is so prompt and decisive that not 
more than fifteen or twenty minutes need elapse after the 
first injection before further measures can be decided on. If 
the poisoning symptoms show no abatement by that time, 
a second injection of the same strength should be made 
promptly, and, unless it is followed by a decided improve- 
ment, a third one again after the same interval. As the 
action of strychnine, when applied as an antidote, is not 
cumulative, no fear need be entertained of violent effects 
suddenly breaking out after these large doses repeated at 
short intervals.” 
Yaws or Framboesia, 
This disease consists of an eruption of yellow or reddish- 
yellow tubercles, which gradually develop into a moist 
exuding fungus, without constitutional symptoms, or with 
such only as result from ulceration and prolonged discharge, 
namely, debility and prostration. Its predisposing causes 
are filth, vitiated atmosphere, and want of animal food in a 
tropical climate. It is more common in the coloured than 
in the white population. It is epidemic and contagious by 
actual contact. The period of incubation ranges from three 
to ten weeks. It is not liable torecur. Its duration is from 
two to four months, but it may last for a year. It frequently 
runs in families, and is apt to be communicated by clothing, 
especially by boots. Children are most subject to it, then men, 
lastly women. The disease often begins with a severe febrile 
attack ; in a few days small spots appear, principally on the 
face, in the axilla, in the neighbourhood of the groin, or on 
the feet. They increase gradually until they are as large as 
a pin’s head, the surrounding skin acquiring an unhealthy 
aspect. In about a week these little tubercular swellings 
exude a thin sanious fluid, forming dry scales or scabs. The 
surface remains covered with these scabs for a week or ten 
days, if undisturbed, during which time a fungoid excrescence 
grows underneath it, so as to form a projecting mass one or 
two inches in diameter. The skin around is hard and firm. 
Crops of yaws arise at different periods. After maturity 
