Henry W. Bates, the famous explorer who ascended the Amazon as far as Teffe, came within 120 miles of the mouth of the Javary River in the year 1858, and makes the following statement about the indigenous tribes of this region: 

The only other tribe of this neighbourhood concerning which I obtained any information was the Mangeromas, whose territory embraces several hundred miles of the western banks of the river Javary, an affluent of the Solimoes, a hundred and twenty miles beyond Sao Paolo da Olivenca.  These are fierce and indomitable and hostile people, like the Araras of the Madeira River.  They are also cannibals.  The navigation of the Javary River is rendered impossible on account of the Mangeromas lying in wait on its banks to intercept and murder all travellers.

Now to return to the letter; I thought that perhaps my English friend had overdrawn things a little in a laudable endeavour to make me more cautious.  In other words, it was for me the old story over again, of learning at the cost of experience—­the story of disregarded advice, and so I went on in my confidence.

When the announcement of the launch’s sailing came, I went immediately for an interview with the owner, a Brazilian named Pedro Smith, whose kindness I shall never forget.  He offered me the chance of making the entire trip on his boat, but would accept no remuneration, saying that I would find conditions on the little overcrowded vessel very uncomfortable, and that the trip would not be free from actual bodily risk.  When even he tried to dissuade me, I began to think more seriously of the Englishman’s letter, but I told him that I had fully made up my mind to penetrate the mystery of those little known regions.  I use the term “little known” in the sense that while they are well enough known to the handful of Indians and rubber-workers yet they are “terra incognita” to the outside world.  The white man has not as yet traversed this Itecoahy and its affluents, although it would be a system of no little importance if located in some other country—­for instance, in the United States.

My object was to study the rubber-worker at his labour, to find out the true length of the Itecoahy River, and to photograph everything worth while.  I had with me all the materials and instruments necessary—­at least so I thought.

The photographic outfit consisted of a Graflex camera with a shutter of high speed, which would come handy when taking animals in motion, and a large-view camera with ten dozen photographic plates and a corresponding amount of prepared paper.  In view of the difficulties of travel, I had decided to develop my plates as I went along and make prints in the field, rather than run the risk of ruining them by some unlucky accident.  Perhaps at the very end of the trip a quantity of undeveloped plates might be lost, and such a calamity would mean the failure of the whole journey in one of its most important particulars.  Such a disastrous