170 PROTOZOAN PARASITISM 



found it in 3.6% of 674 Tamils and in 0.6% of 350 

 Chinese in Malaya. Barrow (1924) found the re- 

 markable proportion of 535 instances of Chiloinastix 

 to 13 of Trichomonas and 10 of Giardia in 725 persons 

 who harbored intestinal protozoa in 100%. Thomas 

 and Baumgartner (1925) found 21 ^^ of the inmates 

 of a New York state school for feeble-minded women 

 to harbor this parasite. Smithies (1926) found it in 

 only 2.6% of his 3780 patients with gastro-intestinal 

 disturbance. Kofoid and Swezy (1920) note that it 

 was found in 4.2% of returned overseas soldiers, in 

 3.5% of soldiers who had not gone out of this coun- 

 try, and in 5.3% of local residents. Hill and Hill 

 (1927) found it in 24% of children of pre-school age 

 in Porto Rico. 



The writer (1928) found 7.5% infection, on the 

 occasion of one immediate examination of purged 

 stool of 1040 patients having some gastro-intestinal 

 disturbance. 



It is usually readily found, when present in active 

 form, by the method given for the examination of 

 stools. Its cysts may also be found in liquid or 

 natural stool in variable numbers and at irregular 

 intervals. 



In active form, described as pearshaped, it is usu- 

 ally more the shape of a carrot. It is usually larger 

 than Trichomonas hominis but averages about 10 to 

 15 microns in length, although forms much smaller 

 and larger may be seen, especially in liquid stools or 

 cultures. Its shape and form is constant as compared 



