1923] Kofoid-Swezy: Pentatrkhomonas ardin delteUi 375 



Dobell and O'Connor (1921), tlie latter decrying but by no means 

 establishing the innocuousness of these infections. Intensive and 

 repeated clinical studies by competent clinicians, with the infecting 

 organism determined by competent protozoologists, will be necessary 

 to settle the mooted point of pathogenicity. The complex interrela- 

 tions in disease and the widespread occurrence of the carrier phase 

 in many infections capable under some conditions of inducing disease, 

 lead one to hesitate to accept as soundly scientitic Dobell and O'Con- 

 nor's sweeping assumptions of non-pathogenicity or their summary 

 dismissal, as being without significance, of the observations of others 

 as to tissue penetration and pathogenicity. More investigation, rather 

 than a dogmatic dismissal, is sorely needed. 



In our experience the common trichomonads of the human 

 intestine, urogenital tract, and mouth all have four anterior, free 

 flagella. In case three only are seen at first, a fourth can be found 

 if the material is so prepared as to be adequately examined. In our 

 experience failure to find the fourth has been due to tlie belief that 

 three is a normal number, or to inexpertness in analysis of speci- 

 mens, or to the disadvantageous position of one of the four flagella, 

 as, for example, when it is hidden under the body. Fundamentally, 

 the reason lies in a failure to observe the differential behavior of one 

 of the anterior flagella. It is the purpose of this paper to give an 

 account of several infections by Pentatrkhomonas ardin delteUi 

 (Derrieu and Raynaud) in man and to direct the attention of proto- 

 zoologists to the distinctness of this genus and of clinicians to the 

 desirability of distinguishing this organism from the seemingly 

 innocuous and more widely prevalent Trkhomonas hominis. 



ACKNOWLEDGMENTS 



We are indebted to Dr. L. M. Boyers, the attending physician on 

 our principal case, for cooperation, and to the patients for prolonged 

 cooperation in providing material for research. Acknowledgments 

 are also made to the Carnegie Institution of Washington, to the Board 

 of Research of the University of California, to Margaret B. Fowler, 

 and to an alumnus of the University of California, for grants which 

 have made possible this investigation, as well as others, on human 

 intestinal Protozoa. 



