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rising from the plant, and J. Bosisto adds a volatile acid.* 
This experiment mentioned shows that men may live in 
health in one of the worst parts of the Campagna with proper 
precautions, and how different would things be if this plan 
were general ; instead of a neglected country with scarcely a 
house, it might be a pleasant habitation, as it once was, for 
many thousands. Still we should not expect this to occur if 
the inhabitants were obliged to take tincture of eucalyptus 
leaves very frequently. Indeed the use of the tincture is 
itself an objection to the experiment. The difficulty into 
which Sir Samuel and Lady Baker got when detained in 
Africa was aggravated by fever of a marsh kind, but seems 
to have been entirely removed when they used the spirit from 
the sweet potato. The fever was not a severe one, but the 
fact injures to some extent the experiment at Tre Fontane. 
If however we look to other countries we are informed 
that the tree itself with its exhalation is quite sufficient to 
render a district healthy, and it is perfectly certain that if 
the oil is efficacious, and the evidence gives faith, 
those who live near must be continually taking in 
doses which must soon equal in amount that usually given 
as a cure. They must in fact be living in a constant vapour 
of this healing oil. In order to produce this condition the 
houses must be surrounded with the trees, and every wind 
will then blow its measure of health. At Tre Fontane this 
is not attempted, and although more ground has been pro- 
mised the monks, it is not promised to extend on every side 
so that they may manage to be surrounded. 
In speaking of the subject it of course occurs to ask : Is 
it really certain that this tree will destroy the malaria, and 
if not certain, will the expense not be a most alarming one ? 
Can any one venture then on giving advice on the subject ? 
This last is the very point which I look on as so clear. 
* See “ Is the Eucalyptus a fever-destroying tree?” by I. Bosisto. 
Roy. Soc. of Victoria, 1874. 
