myself ou Uie banks of the Rio Bicudo 

 where the works on the railroad lingered 

 belated by the epidemic. The malaria pro- 

 phylaxis was unterlakeu with the most 

 satisfactory results and regular work on 

 the railroad was once more begun. 



We remained more than a year in 

 this region without becoming aware of 

 the existence in the local huts, of a 

 blood-sucking insect known popularly 

 the name of barbeiro, chupão or 

 chupança. By this time we had already 

 had the opportunity of carrying out lo- 

 cally a good deal of clinical observation 

 and of studying a great number of ca- 

 ses not only amongst those sul)ject to 

 malarial infection, in the valleys of big 

 and small rivers but also among the 

 inhabitants of mountainous regions who 

 were entirely exempt of this disease. 



And from that time on, experimental la- 

 boratory methods and the most careful 

 semiotic consideration of the cases were 

 alike of no avail in diagnosing some of 

 the cases submitted to us. In these there 

 remained unknown something new in 

 the dominion of pathology to stimula- 

 ted our curiosity. 



On a journey to Pirapora and while 

 spending the night in an engineers' camp 

 Dr. BELISARIO PENNA and I first ma- 

 de the acquaintance of the barbeiro, 

 Shown to us by Dr. CANTARINO MOT- 

 TA, chief of the engineering committee. 

 Once we had heard of the blood- 

 sucking habits of this insect and of its 

 proliferation in human dwelling-places, 

 we became very interested in knowing 

 its exact biology and above all in ascer- 

 taining if by any chance it were as I 

 immediately supposed, a transmitter of 

 any parasite of man or of another ver- 

 tebrate. 



The rôle of several blood-sucking 

 insects in the transmission of human 

 diseases and of several trypanosomiases 

 of mammals, directed my line of thou- 

 ght and led rae to obtain some more 

 specimens of tlie insect, so as to search 



for the parasites which it might har- 

 bour in its digestive tube and salivary 

 glands. Dissecting the insect, / found in 

 the poslerior intestine of each one nu- 

 merous flagellates with the appearance 

 of crithidias. This fact elicited two hypo- 

 theses, either the flagellate was a harm- 

 less natural parasite of the insect, or 

 else it represented a stage in the evolu- 

 tion of a hsemo-flagellate of some verte- 

 brate perhaps even of man. 



Previously I had found a new spe- 

 cies of trypanozome in the monkey Cal- 

 lithrix (Callithrix penicillata) and given 

 the frequency of the infection of mon- 

 keys by Trypanosoma minasense, the 

 species I described, I supposed the crithi- 

 dias seen in the intestine of the barbeiro 

 to be a phase in the evolution of this 

 trypanosome which would then be trans- 

 mitted by the insect. And as all the 

 monkeys of the region proved to be in- 

 fected the experiments of transmission 

 with the purpose of confirming this hypo- 

 thesis could not be carried out for obvious 

 reasons. For this reason I sent some of 

 the insects to my unforged table chief 

 OSWALDO CRUZ, so that they should 

 be allowed to suck healthy monkeys of the 

 genus Callithrix. 20 or 30 days later 

 when once again back in Manguinhos, I 

 examined the blood of one of these 

 monkeys that had been sucked by bar- 

 beiros and found in it a trypanosome, 

 which at first sight and before exami- 

 ning it by the technical methods I took 

 to he Tnjp^mosoma minasense. Añer ha- 

 ving seen the flagellate alive, between 

 cover-glass and slide I made some fixed 

 and stained preparations in which it was 

 seen to show characters entirely distinct 

 from those of Trypanosoma minasense 

 and to show no similarity to any other 

 trypanosome. It was undoubtedly a now 

 species whose chief character lav in its 

 blepharoplast, the biggest I had yet seea 

 and located at the hind end (the end 

 opposed to the free flagellum). 



