INSECT TORMENTS 17 



act differently upon the atmosphere than soil and dust ; but it w-ill be prudent to 

 make no definite assertions upon this subject. Chemistry has not yet solved any 

 of the numerous mysteries of the unhealthiness of the air. It has taught us only 

 that we are ignorant of many things which we thought we knew fifteen years 

 ago, thanks to the ingenious dreams of the ancient eudiometry. 



" What is less uncertain, and confirmed, so to speak, by daily experiences, is 

 that on the Orinoco, the Cassiquiare, the Eio Caura, and everywhere where the 

 air is very unhealthy, the bite of the mosquitos increases the disposition of the 

 organs to receive miasmatic impression. When during whole months one is ex- 

 posed night and day to the torment of insects, the continual irritation of the 

 skin causes febrile movements and depresses the functions of the stomach by 

 the effect of the antagonism, so long kno'WTi, between the dermal system and the 

 gastric system. One begins to digest witli difficulty; the inflammation of the 

 skin brings about abundant perspiration ; one can not quench his thirst ; and 

 to his always increasing impatience follows, with persons of weak constitution, a 

 condition of low spirits during which all the pathogenic causes act with force. 

 Today it is not the dangers of navigation in little canoes, it is not the savage 

 indians, or the serpents, the crocodiles, or the jaguars, which makes Spaniards 

 fear the voyage up the Orinoco ; it is, as they say naively, ' the sweats and the 

 flies.' Let us hope that man, in changing the surface of the earth, will little by 

 little bring about a change in the constitution of the atmosphere. The insects 

 will diminish when the old trees of the forest will have disappeared, and one 

 will see in these desert countries the rivers bordered with villages, the plains 

 covered with pastures and cultivated fields. 



" Whoever has lived a long time in countries infested by mosquitos will 

 have proven, as we have, that there is no radical remedy against the torment of 

 insects. Indians covered with onoto, with bolary earth, or with turtle oil, 

 are every instant slapping their shoulders, their sides, their legs, almost as 

 though the body had not been painted. It is doubtful in general whether paint- 

 ing is a relief — certainly no great relief. Europeans recently arrived on the 

 Orinoco, on the Eio de la Magdalena, on the Guayaquil or the Chagres rivers (I 

 mention the four rivers where the insects are the most numerous) at first cover 

 the face and the hands. They soon find the heat too great, and they are tired of 

 being completely inactive, and end by uncovering. Persons who do not wish to 

 do any kind of work during the nfivigation of the rivers can bring from Europe 

 an especial kind of clothing in the form of a sack under which they can rest 

 hidden, opening it only every half hour. This sack should be held open by 

 whalebone hoops, for a simple mask and gloves would be hardly bearable. Sleep- 

 ing upon the earth, upon skins or in hammocks, we have not been able in the 

 Orinoco region to use mosquito bars, A mosquito bar is useful only when it 

 forms about the bed a tent so well closed that there is not the least opening by 

 which a mosquito can enter. This condition is very difficult to bring about, and 

 often one is forced (for example when going up the Rio de la Magdalena, where 

 they travel with these mosquito bars), in order not to suffocate with heat, to get 

 out from under his bar and to walk in the open air. A mild wind, smoke, and 

 strong odors afford almost no relief in the places where these insects are very 

 numerous and very voracious. It is wrongly stated that these little insects avoid 

 the odor of the crocodile. We were horribly bitten at Bataillez on the road from 

 Carthagena des Indes to Honda, while we were dissecting a crocodile eleven 

 feet long and which infected the whole atmosphere of the neighborhood. The 

 indians recommend the exhalation of burnt cowdung. When the wind is very 

 strong and accompanied by rain the mosquitos disappear for some time. They 

 bite the most cruelly on the approach of a storm-, and especially when the thunder 

 is not followed by showers. 



