20 METHODS OF EXAMINING FECES FOR PARASITISM. 



Where small amounts of feces are used, two pieces of brass tubing, 

 2 inches in diameter and l\ inches high, beveled to fit one in the 

 other, and the lower one furnished with three projections to hold it 

 on glassware of not over 3 inches in diameter, are used to hold the 

 bolting cloth of the silk sieve, the cloth being caught and held taut 

 by the beveled surfaces. Where large amounts of feces are used, and 

 large amounts not to exceed 4 or 5 ounces should be used whenever 

 obtainable, two enameled tin pans, with a bottom diameter of 4^ 

 inches and with the bottom cut out so as to leave a narrow flange, are 

 used in place of the brass tubing. The cloth is held between the upper 

 flanges of the tw y o tins, and the cloth and flanges held together by 

 four small clothespins of the sort provided with a wire spring to 

 hold the jaws together. This device I also owe to Dr. Cobb. The 

 sieve formed of the tins and the bolting cloth is the right size for 

 use with a jar 10 inches high and 5 inches in diameter (see fig. 1, c). 

 When necessary a soft brush is used to brush the feces through the 

 fine brass sieves or the silk cloth. Cobb (1904), as previously noted, 

 uses a brush for the same purpose. These sieves will work better if 

 water is poured through them or if they are dipped in w T ater before 

 the fecal matter is poured on. 



The sieves, as well as all other apparatus coming in contact with 

 the fecal material, are washed promptly with boiling water, the sieves 

 being also scrubbed with a stiff brush. This prevents any parasitic 

 material from remaining to contaminate a subsequent fecal specimen, 

 and thereby giving inaccurate findings. A microscopic examination 

 of the silk sieve shows that it w r ashes clean very readily, and when 

 rinsed retains very little of the material poured on it. Experiment 

 shows that eggs pass through this cloth very readily, less than half 

 of 1 per cent of even such large eggs as Toxocara remaining when 

 the fecal matter is first brushed through. A smear made from the 

 residue on the bolting-cloth sieve showed 4 eggs in one case where 

 the slide preparation from the centrif uged sediment showed 860 eggs ; 

 another smear from the residue on the bolting cloth showed 1 egg 

 where the slide from the sediment showed 475 eggs. In the latter 

 case, a fair estimate of the amount of material on the cloth and the 

 amount from which the smear was made indicates that there were 

 probably not more than 10 eggs left on the cloth, while thousands 

 had passed through it. Those that are left are held by the jelly-like 

 residue obtained at this point, and not because the screen mesh is 

 defective or too small. The writer is not aware of any parasite eggs 

 which are too large in their smaller diameter to pass through a mesh 

 with a diameter of 0.117 to 0.134 millimeter. The number remain- 

 ing after clean water has been poured through the cloth into the jar 

 is entirely negligible. 



In working with human feces, or where dangerous infection may 

 be present, the silk cloth may be kept in a jar of formol solution 



