Tí}e Discovery of Trypanosoma Cru3Í ano of 

 American Trypanosomiasis 



Historic retrospect 



by 



I3R. caíalos en ao- as 



Directeur of tlie Instituto Oswaldo Cruz. 



The discovery of araericaii Irjpa- 

 nosoraiasis and chiefly the methods of 

 reasoning which led to definitive re- 

 sults, furnish a new line of action for 

 conducting similar research-work yet to 

 be undertaken with a view to solving 

 other obscure problems of human patho- 

 logy. 



This biological observation was car- 

 ried out in a way completely different 

 to that usually employed in recognising 

 the etiology and pathology of diseases 

 or in describing new ones. Furthermore, 

 as in this discovery there are to be 

 found interesting aspects and incidents 

 which may be of use to other research 

 workers, there follows an exact and mi- 

 nute description of the facts especially 

 those concerning the more important 

 points. 



The discovery of the parasite here 

 preceded the recognition of the disease 

 and when in the blood of a feverish 



child I found the pathogenic trypanoso- 

 me I had already acquired a complete 

 notion of its biology. 



But for greater clearness it is more 

 advisable to expose the facts in their 

 uninterrupted order : 



.Vs a consequence of the outbreak 

 of a malaria epidemic amongst Govern- 

 ment workmen on the Central Railway 

 of Brasil, in the valley of the Rio das 

 Velhas (Slate of Minas Geraes) the Mi- 

 nister MIGUEL CALMON applied to OS- 

 WALDO CRUZ for steps to be taken. 

 OSWALDO CRUZ immediately com- 

 plied, intent as he was on proceeding 

 with the anti-malarial campaigns suc- 

 ccesfully undertaken in other parts of 

 the country and decided to entrust me 

 with lhe sanitary measures. 



Together with Dr. BELISARiO 

 PENNA whom I invited to be assistant 

 in this commission, I started out for the 

 interior of Minas Geraes and installed 



