OF WASHINGTON, VOLUME XV, 1913 109 



is wanting in many places where there are Anophelidse, which are 

 by no means ubiquitous. 



My paper on forest malaria has been everywhere accepted with- 

 out contradiction, and since I wrote it the facts have been confirmed 

 by several people. Dr. Chagas observed another epidemic under 

 absolutely similar conditions and near the same place and author- 

 ized me to state that he is convinced of the correctness of my expla- 

 nations, which is of interest, as he has observed several epidemics 

 of malaria in different places and studied the Anophelidae found. 

 I myself have seen another epidemic and there are some more on 

 record showing the occurrence of epidemical malaria in places where 

 there are plenty of epiphytic Bromeliacese and no swamps. It is 

 now a generally recognized fact in this country that all the great 

 works. of engineering, where hundreds and thousands of workmen 

 have to sleep in the open air, will lead to epidemical outbreaks of 

 malaria, even in quite uninhabited regions where there are swamps 

 clue o the perodical inundations of the rivers. The observations 

 in the uninhabited mountain woods of the coast range are quite 

 analogous and just as certain, with the difference that the higher 

 places get infected later and never in the cold season. On the 

 other hand the very same workmen have clone the same work in 

 the dry Campos regions and in the woods of the interior where 

 there are no Bromelia Anophelidse without the slightest malarial 

 manifestations. 



Of course a few chronic malaria patients must be present and 

 these will be found amongst the workmen who previously took part 

 in. similar work, but these people, far from being quite healthy, 

 could be picked out and excluded, as I proposed long ago. 



In this country Cellia argyrotarsis is much more responsible for 

 the spreading of malaria than albimana. Both the species are 

 frequent in uninhabited places and only come near the houses when 

 these are built in swampy regions, excepting very few stragglers. 

 That they do not want or prefer human blood is shown by the quite 

 well known fact here that they prefer the horse to the rider and 

 large numbers of them might be caught on horses by persons who 

 do not get bitten themselves. The same is true for all other species 

 of Anophelidae. 



Now it is quite natural that the workmen in uninhabited places 

 where big game is rare will attract the mosquitoes and if they stay 

 long enough in the same place the epidemic will follow the increase 

 of the infection in the mosquitoes who themeslvcs augment in num- 

 ber through the facility of alimentation. It is a well established 

 fact that a species might be an excellent intermediate or definite 

 host of a parasite quite new to the country because the host for the 

 other stage has only been introduced recently. 



