150 



every place at which the terrible malady manifests itself periodically. 

 The investigation may point out the right path — which seems to us well 

 marked out by studying what takes place in Rio de Janeiro 



The v How fever has appeared in Para; while at Maranhao, Ceara, 

 Rio Grande do N<>rte, and Parahiba we are not awa-e that such a 

 disease has shewn itself. Does this discrepancy proceed from the beach 

 in the three former provinces being sandy, and the mangroves intact in 

 the last. 



Are there in Para uncovered mud-banks which are the cause of 

 analagous putrefaction to that of the bay of Rio de Janeiro ? Does the 

 mangrove exist there ? Has it been devastated on a large scale ? 



The yellow fever has shown itself at Pernanibuco, Bahia, Santos, and 

 after 1870 at Paranagua. At >Sta. ( atharina and S. Pedro do Sul such 

 a scourge is unknown. Why is it that some parts of the sea-board of 

 Brazil should be attacked and others not ? Why do not near provinces 

 in identical atmospherical conditions import and export; the scourge 

 from one to the other ? If it is true that we imp rt yellow fever, how 

 is it that we do not export it to Sta. Catharina and Rio Grande do Sul, 

 at so few days voyage from hence ? Why did not Pernambu ,-o export 

 it to Parahiba, and so on successively ? 



Everything conspires to show how there is a cause on the sea-side, 

 and how the difference of the nature of the coast rules, or not, the fever. 

 The resistance offered to it by the interior of the country is a proof of 

 this. The cause, in our opinion, is the devastation of the marine forest, 

 the cutting down of the precious trees, in which observation has shewn 

 us an error of f :tal consequence. * 



It is not necessary to proclaim the beneficial influence of forests 

 cultivated in the neighbourhood of the great centres of population. 

 Nevertheless, we never even heard speak of our marine forest ; and we 

 possessed a splendid one, rich, and eminently appropriated to the ren- 

 dering of the city of Rio de Janeiro healthy. That forest afforded us 

 for long years combustible w iich appeared to be inexhaustible ; but 

 the good quality of its wood aided to abbreviate the term of its 

 destruction. 



Whet er or not it be mere conjecture, it is a certain fact that as long 

 as we had a marine forest we had no yellow fever. The advent of the 

 latter coincided with the disappearance of the former. If this be not 

 sufficient to determine the relation of the cause with the effect, it certainly 

 constitutes an element which is not to be despised." * 



The yellow fever has not yet invaded the interior of Brazil, and it has 

 shewn itself in some places, and not in others, of the coast ; it has pre- 

 vailed for many years, and at more or less too short intervals for the 

 contagion to have amplified the «rea (in case it found localities hitherto 

 exempt from it) and the means adapted for planting the seeds of the 

 malady. 



Therefore it is from the mud of the sea that the cause ought to be 

 sought ; and as the scourge did not, for long years, attack all the in- 

 habited places washed by the ocean, it is to be inferred that such a cause 

 is not virtually in the waters, but in the conditions which modify them, 

 saturating them with morbid elements. 



In concluding, I would say that no conviction was ever more profound, 

 or even calmly formed, than that which I have manifested. It is now 



