1.An intensive study of third-class patients on the medical service of the Peking Union Medical College Hospital was undertaken to determine the importance of parasitic infection in clinical diagnoses in North China.
2.Sixty cases were studied. Each case was under careful scrutiny for a period of ten days or more, during which time every stool passed by the patient was examined. In all, 1409 stools were studied, or an average of 23.48 per patient.
3.Controlled methods of preparation of the stool for examination indicated that concentration methods were valuable only where a single specimen of stool was available for study. In cases where large numbers of stools of the same patient were examined concentration methods added only ten per cent to the findings. Forty per cent of the infections were diagnosed after the first day, 35 per cent of which were diagnosed first from unconcentrated preparations.
4.Eighty per cent of the cases studied harbored intestinal entozoa. While this infective incidence is comparable to that of a sick population in Central China, it is less intensive than the latter. The respective indices for the two areas are as follows: Central China (Wuchang survey), protozoa, 228.7; helminths, 234.3; North China (present study), protozoa, 101.6; helminths, 88.03.
5.The clinical significance of the study is demonstrated by the fact that 53.3 per cent of the series harbored clinically important parasite infections. Twenty per cent of the cases had a major diagnosis due to parasites; 46.6 per cent had a minor diagnosis of parasites; 13.3 per cent of the cases had both major and minor diagnoses occasioned by infections of the digestive tract due to parasites.
6.Nor proof can be advanced from the present study regarding flagellate entozoa in amoebic dysentery that there is a necessary relationship between the two infections.
7.In the cases studied at least 89 per cent of the patients secured their infections in the North China nosogeographic area. They belong to the lower middle class and the poor class, which groups, on account of undernourishment are likely to be more troubled with clinically important infections than are the upper classes.
8.The Chinese as a people are not less susceptible to parasitic infection than other peoples, although light infections among Chinese are less likely to be clinically significant than in Occidentals living in China.
9.Improper disposal of nightsoil is responsible for all of the helminthic infections in the intestinal tract of man in North China as determined by this study.