2i8 RESEARCH IN PROTOZOOLOGY 



alteration of its prevailing characters. These matters naturally 

 will be looked after by the clinical man. 



The so-called "provocative methods" employed in the detection 

 of infections with Entamoeba histolytica require little attention. 

 If they possess any virtues at all these lie in the field of clinical 

 medicine. For humane reasons some of them never should be used. 

 I mention them only that I may emphasize the point that such 

 methods have no place in research. 



Careful macroscopic examination of the specimen should be 

 made as soon as it reaches the laboratory and careful note should 

 be made of the general physical characters. 



We shall now briefly consider a few points of importance in 

 the study of bowel discharges. 



To begin : It is vitally important to distinguish between stools 

 and exudates. A ''stool" must contain fecal matter. The mucoid 

 masses passed in dysentery are not "stools." However, an exudate 

 may be found in a stool, or, the entire movement may consist of 

 exudate. Exudates are the product of inflammation and are com- 

 posed of fluids and cellular elements derived from the tissues of 

 the subject. Fecal matter does not enter into their composition. 

 These distinctions should be accurately recorded. 



There seems also to be some misapprehension as to the use of 

 the term "acholic." It often is bestowed on pale stools which, on 

 application of a chemical test for urobilin, are shown to contain 

 an abundance of that substance. It will be seen, therefore, that 

 the eye does not furnish a reliable means of determining whether 

 or not a stool is acholic. Accuracy in this respect may be very 

 important; therefore, it is wise to- apply Schmidt's mercuric 

 chloride test before pronouncing a stool acholic. More exact work 

 will require the application of the Wilber and Addis method.^ 



Dysenteric movements frequently are atypical. In the strict sense 

 they are small and mucoid and often blood-streaked, but that is 

 usually when the attack is well under way and the bowel has been 

 cleared of fecal matter. Amoebic dysentery movements often are 

 feculent, loose and blood-streaked. On the other hand, the evacua- 



^ The stools of sprue often are spoken of as acholic because of their pale 

 coloration. As a matter of fact, the characteristic color of sprue stools is 

 due largely to their high content of fat. Moreover, the bile pigments become 

 converted to "colorless urobilinogen." This substance always occurs in 

 excess when a severe aplastic anaemia complicates the sprue. 



