26 METHODS OF EXAMINING FECES FOB PARASITISM. 



canting was shaken vigorously and divided into two equal parts, one 

 being centrifuged and washed, the other being poured onto the 10 

 cubic centimeters of water in the burette. As the sediment settled 

 it could be traced by the discoloration of the water, and when the 

 discoloration reached the bottom, one preparation was made by open- 

 ing the stopcock and taking a drop of water on the slide. Other 

 slides were made at intervals up to an hour. In one specimen of dog 

 feces where there was an infection Avith Dipylidium, Ascaris, Tri- 

 churis, and Ancylostoma, the best of six slides made in this way 

 showed a total of 27 eggs, while a slide made after centrifuging with 

 calcium chlorid of 1.250 specific gravity showed 77 eggs and one 

 centrifuged in water alone showed 181 eggs. In the last case there 

 w r ere more eggs of any one of the four species of parasites present 

 than there were of all together in the best of the slides made by the 

 burette method. 



In another test, feces from a dog infected with Toxocara and Tcenia 

 were tested by the burette method without the clean water at the bot- 

 tom, the sediment obtained after screening being poured into the 

 empty burette. The best of two slides made by this method showed 

 58 eggs, a slide made by the smear method showed 46 eggs, a slide 

 made by centrifuging in the solution of 1.250 specific gravity showed 

 117 eggs, and a slide made after centrifuging in Avater alone shoAved 

 215 eggs in one-fourth of the cover-glass area. The slide started to 

 dry at this point and the count was discontinued. The estimated 

 total for the slide was of course four times 215, or 860 eggs. A 

 smear preparation made from the residue on the bolting-cloth sieve 

 shoAved four Toxocara and no Tcenia eggs. 



GASTEIGER'S FILTER METHOD. 



A test of the filter paper and funnel as a substitute for the centri- 

 fuge indicated at once that nothing was gained by scattering a sedi- 

 ment over a filter paper instead of concentrating it in the bottom of 

 a tube. The method was also S!OAV and offered the usual chance of a 

 break in the filter paper, necessitating a second filtration. I can not 

 imagine any use of the filter in fecal examinations for parasites that 

 would not be better subserved by the use of the sieve folloAved by 

 centrifuging. 



BASSES CALCIUM CHLORID CENTRIFUGE METHOD. 



Inasmuch as Bass's salt solution method is held by its author to 

 be inferior to the calcium chlorid method, it need only be noted here 

 that in the few tests of the first-named method made by the Avriter 



