A COMPARATIVE STUDY OF METHODS OF EXAMINING 

 FECES FOR EVIDENCES OF PARASITISM. 



INTRODUCTION. 



Having occasion to make numerous examinations of feces for evi- 

 dences of parasitic infection, the writer lias devoted some time to 

 developing a satisfactoiy method which would be capable of general 

 application in routine examinations and which would give the surest 

 results in the shortest time, one which would detect any existing in- 

 fection, even though light, in any kind of feces, so far as the existing 

 limitations of fecal examinations permit. The different methods 

 which have been used and advocated, most of them being methods 

 used in examining human feces, were tested on feces of various kinds. 

 This paper deals with the results of these tests. The method which 

 gave the most satisfactory results and which is hereafter referred 

 to as the writer's method is a modification of previous methods. 



Fecal examinations are of two sorts first, examination with the 

 naked eye for gross evidence of infection in the shape of entire' para- 

 sites or fragments, and, second, microscopic examination for para- 

 site eggs, embryos, etc. The first is very commonly, perhaps wrongly, 

 neglected; the second is commonly used and will be considered first 

 here. 



METHODS OF MICROSCOPIC EXAMINATION. 

 SMEAR METHOD, 



The microscopic method which is commonly used and advocated 

 is what may be called the smear method. A small particle of feces 

 is taken up with a toothpick or stirring rod, smeared on a glass slide 

 in a drop of water or salt solution, covered with a cover glass, and 

 examined under the miscroscope. This method is the oldest and the 

 simplest, can be used under almost any conditions, and, in that it calls 

 for no equipment beyond a toothpick, a slide and cover glass, and a 

 microscope, is also the most inexpensive. It is usually considered 

 satisfactoiy. providing a numl)er of slide preparations, commonly 

 10, are examined. This method has been repeatedly commended by 



