204 RESEARCH IN PROTOZOOLOGY 



has compared supposition with the fruits of a wider observation 

 and the analysis of concomitants. 



To begin, let me state my belief that the evidence in our posses- 

 sion to-day points to Entamoeba histolytica, Balantidium coli and 

 Eberthella {Bacillus) dysenterice as being the only organisms 

 which have been proved to cause dysentery in the strict sense. 

 There are, to be sure, numerous other protista, and a few 

 METAZOA, that have been named as causes of dysentery or, at 

 least, said to be related to the phenomena of dysentery, and they 

 furnish the greater number of the unsolved problems relating to 

 the diagnosis of dysentery. Many of the remaining problems are 

 furnished by a group of so-called constitutional diseases of uncer- 

 tain etiology, part of the symptomatology of which is referable 

 to the alimentary tract. Anemia, of the primary type, may be 

 mentioned as one of the more important members of the latter 

 group. 



Adequate inquiry into the phenomena and causes of these condi- 

 tions, therefore, involves excursions into the fields of zoology, bac- 

 teriology, pathology, serology and clinical medicine. Accordingly, 

 diagnosis of the dysenteries may be said to rest upon three factors : 

 the microorganisms present ; the evidences of local reaction in the 

 intestine as manifested in the bowel discharges, and the general 

 physical state of the patient as ascertained by clinical study zvhicli 

 sJioiild include tJic consideration of all concomitants. In other 

 words, in the study of a given organism to determine if it is the 

 cause of dysentery, it not only is prudent — it is important — first 

 to ascertain with certainty whether a state of dysentery exists. 

 Moreover, the mere presence of a pathogenic organism in the 

 bowel contents of a person suffering from an intestinal disorder 

 does not necessarily settle the question of diagnosis — on the con- 

 trary, it may complicate it exceedingly. The phenomena must be 

 studied from a broad viewpoint. Not only must the organisms 

 present be studied, the reactions of the infected person must be 

 interpreted and an effort made to harmonize the two. 



BACILLARY, AMCEBIC AND BALANTIDIAL DYSENTERIES 



In laying down our problems let us start with bacillary dysen- 

 tery for it affords the most striking and easily analyzed picture of 

 all the acute intestinal conditions. 



Preeminent among the problems to be solved is the determina- 



