37 
is our intention to defer the publication of our clinical report until 
we can present a more complete monograph embracing the patho¬ 
logical and experimental work of the laboratory. Autopsies have 
been practised on all the available material and careful records kept 
of the numerous cases seen during our residence in Manaos. 
Ronald Ross* has always pointed out that ‘ a locality is malarious 
only when it contains persons already infected with the parasite, and 
also sufficient numbers of the proper species or varieties of 
Anophelines to carry infection to healthy persons.’ Gorgas.t in his 
anti-yellow fever work, terms this the yellow-fever ‘point,’ and 
contends that a certain proportion of Stegomyia mosquitos must be 
present in a locality for the spread of yellow fever. If the number of 
Stegomyia remain above this ‘ point,’ the locality will continue to 
have yellow fever as long as non-immunes are present, no matter how- 
much fumigation is done or how carefully the sick are isolated. If 
anti-stegomyia measures are vigorously carried out and the Stegomyia 
so reduced in number that they are below this point, then yellow fever 
disappears Gorgas thus explains the success of the Havana and 
Panama measures, and the reason why so long a period elapsed 
between the active starting of the campaigns and the stamping out 
of yellow fever in these places. 
Can Manaos be freed from yellow fever ? 
We see no reason why yellow fever should not be absolutely 
stamped out of the whole of the Amazon district and the cities of 
Para and Manaos in Brazil and Iquitos in Peru freed of this scourge. 
To attain freedom from yellow fever will take time and money, 
and it will require the active co-operation of the authorities, the 
Brazilian and the foreign residents of the city. Stegomyia will have 
to be continually attacked. War cannot be waged against this 
mosquito for a few months only. It must be fought throughout the 
whole year. We do not have to go outside of Brazil to find an 
example of what can be accomplished in fighting yellow fever. The 
city of Rio de Janeiro was a veritable * inferno,’ but, thanks to 
Oswaldo Cruz, yellow fever is conquered. We know of no more 
striking example of what sanitation can accomplish than is evidenced 
Ross, Ronald. Report on the prevention of malaria in Mauritius, 1909. 
.. ^ Gorgas, w. C. Method of the spread of Yellow Fever. Proceedings of Canal 
Zone Medical Association, 1908. 
