30 METHODS OP EXAMINING FECES FOR PARASITISM. 



additional solution of material accomplished by the use of these 

 chemicals was but slightly more than the solution accomplished by 

 water alone. In two other cases where dog feces had been allowed 

 to stand a long time in water and had been shaken up for four or five 

 minutes before being sieved and centrifuged, the resultant sediment 

 of 1.4 cubic centimeters was actually increased after the application 

 of Telemann's reagents followed by centrifuging to a flocculent sedi- 

 ment of 1.9 cubic centimeters. 



The results of comparative tests of Telemann's and the writer's 

 method were quite unexpected, as the writer had used Telemann's 

 method for a year and only abandoned it when its inapplicability in 

 the case of sheep feces became to.o evident to overlook. As has been 

 stated previously in this paper, the success of Telemann's method ap- 

 pears to be due more to the efficiency of a slight solvent action in 

 mechanically breaking up feces and putting them in condition to 

 sieve, than to an extensive solvent action. Much that might be dis- 

 solved in the chemicals is soluble in water, much that might be dis- 

 solved is perhaps taken out by the screen where water alone is used, 

 and the fact that the slight solvent action breaks up the feces and 

 makes them easy to sieve seems to be the feature to which the results 

 obtained by this method are to be attributed. 



The feces of herbivora have little material that is soluble in Tele- 

 mann's reagents, and the breaking up secured by them is inferior to 

 that secured by the use of the writer's method. Human feces break 

 up rapidly in Telemann's reagents, but the method advocated by the 

 writer takes about the same time and gives as good results. Of Tele- 

 malm's method, Dock and Bass (1910) say: 



We have found the method admirable with some stools, but in others not 

 enough solution occurs to permit a concentrated layer of eggs to be thrown 

 down. 



Telemann's method has one disadvantage which neither Telemann 

 (1908), Pfister (1909), nor Quadflieg (1909) mentions in connection 

 with it it injures the microscope. The fumes of pure hydrochloric 

 acid attack the lens mountings and also the stage and the lenses 

 themselves. The use of vaseline to seal the edges of the cover glass 

 affords an uncertain protection, and the use of high powers under 

 such circumstances is decidedly unsafe. In the writer's opinion the 

 injury to the microscope would of itself be sufficient reason for dis- 



carding this method. 



CULTURE METHODS. 



Quadflieg (1909) has recommended using culture methods as an 

 aid in detecting infection. Tests of this method did not indicate that 

 it added to the certainty of detecting infection, though live embryo 

 nematodes could be detected by the use of a dissecting microscope 



