12 HUMAN INTESTINAL PROTOZOA IN THE NEAR EAST 



the collection of samples for many other purposes, as, for instance, 

 examinations of typhoid carriers. 



In all the examinations of men in camp we have examined only 

 single samples from each man. We recognize that in so doing a 

 number of cases of infection are missed, for the protozoal infections 

 of the human intestine are very irregular as judged by the appear- 

 ance of the protozoa in the stool. 



The Value of a Single Examination in determining Infections. 

 If one looks through the protocols of the cases of E. histolytica 

 infection at the end of this report it will at once be seen that 

 many protozoal infections which were not apparent at the first 

 examination of a patient's stool appeared later on. This was 

 true of all the protozoa found in the intestine. On several 

 occasions cases which have been treated for a lamblia or other 

 infection have, during the control, suddenly given evidence of 

 an infection of E. histolytica. Such observations -prove to us 

 clearly that a single examination of any individual may give an 

 erroneous view of the infection. In order to arrive at some idea of 

 the error we undertook the examination of a group of healthy men. 

 The permanent Eoyal Army Medical Corps staff of the Mustapha 

 Training Depot were chosen for this purpose. A series of ninety- 

 two men were examined for a number of days. It was intended 

 originally to examine them all every day, but owing to the changes 

 in the staff and the movements of troops this was impossible. 

 However, some of the men were examined twelve times, others 

 eleven, others ten, and so on during the twelve days, and the results 

 have been arranged in Table I, in the order of the number of 

 examinations. In the first column have been placed the complete 

 findings resulting from all the examinations and in the twelve 

 columns following the result of the daily examinations. Thus case 

 Thomas was found to have E. coli cysts (E.c.c.), E. histolytica 

 cysts (E.h.c.), free amoebae (E.f.), lamblia cysts (L.c.), E.nana cysts 

 (E.n.c.), and E. nana free (E.n.f.). On the first examination, 

 however, were found only E. coli cysts, lamblia cysts and E. nana 

 cysts, and it was not till the sixth examination that E. histolytica 

 cysts appeared. It will be noted that the majority of cases 

 examined yielded results of this kind. Thus, looking at the 

 E. histolytica infections alone, it will be seen that this parasite 

 was found in twelve of the ninety-two cases, but that in only four 

 of these was it found at the first examination. If we are to accept 

 this finding it would mean that all the figures resulting from a 



