4 INTRODUCTION 



Weil-Felix reaction was employed and its diagnostic usefulness 

 confirmed (see p. 33) in eighty-three cases. 



Although the work of the Commission was planned inde- 

 pendently, the results, both in regard to the etiology and pa- 

 thology of typhus, prove in the main to be confirmatory of the 

 work of many widely separated workers. We have added some- 

 what to the knowledge of the pathology and extended con- 

 siderably the knowledge of the etiological agent. In general 

 our work serves as a carefully conducted control to quite a 

 number of researches made under less favorable circumstances 

 in several countries. 



For the study of a human disease transmitted by an inverte- 

 brate host two things are essential: a supply of patients in- 

 fected with the disease to be studied, and an uninfected supply 

 of the invertebrate hosts. The Commission had both at its 

 command. The observations recorded in this report are based 

 upon one hundred and eighty-one cases of clinically well- 

 established typhus. The patients were selected from among 

 general admissions to the St. Stanislaus Hospital, and were 

 cared for in our wards. The lice employed in this study were 

 taken to Warsaw from areas in North America and in Great 

 Britain, where typhus is not endemic and were fed upon mem- 

 bers of the Commission during the entire period of the research. 

 Extensive control examinations of the lice used were made at 

 the beginning and conclusion of the work. 



