240 
Intestinal Protozoa of Man 
diminished, I examined a series of supposed healthy Egyptian labourers with 
a view to ascertaining the percentage of Entamoeba histolytica carriers in this 
large co-operating force. 
The number of cases examined, with the macro- and microscopical appear¬ 
ances of the stools and the number of cases in which the different Protozoa 
were found, together with the percentages of each, are given for each month 
in the appended tables. 
After the laboratories had been established for some time all specimens 
arrived fresh and were therefore easily examined. At first the following 
difficulties were encountered. 
1. Specimens collected over night and sent to the laboratory next day 
arrived stale; free Protozoa were generally dead or degenerated and could 
not be identified. Orders were circulated that only material passed on the 
day of transmission should be sent and that transport should be as rapid as 
possible. 
2. Specimens were sent in which the cell-elements were dead or degener¬ 
ated owing to: 
{a) The stools having been passed into pans along with the urine. 
Urine bottles were therefore provided and instructions issued for the passage 
of urine and faeces into separate utensils. 
( b ) Pans being used which contained, or had recently been cleaned 
with, antiseptics. Orders were issued that stools from which samples were 
required should only be passed into pans containing no antiseptics, or which, 
after antiseptic treatment, had been thoroughly washed and dried. 
3. Admixture of sand with specimens. This was difficult to overcome. As 
it rendered the adjustment of cover-slips necessary for fine focus impossible, 
attendants were requested to see that receptacles had tight-fitting covers, 
which were to be removed only immediately before use, and to be replaced 
immediately afterwards. Patients also were provided with toilet paper and 
they were advised against letting it come in contact with the desert sand. 
Methods of Examination. 
When present in a specimen, blood and mucus and faecal material were 
always examined. 
Films were studied by the method used by Wenyon in London, and Wenyon 
and the writer in Alexandria, but when I discovered that Protozoa could be 
seen as small shiny dots with the §" objective, I always—before using the 
J" and —made a rapid preliminary examination of three preparations 
with the §", and by this means I recognized many scanty infections that 
otherwise might, I think, have been overlooked. AVhen using the f" objective 
one learns with a little practice to differentiate between Protozoa and small 
vegetable organisms which at first appear like protozoal cysts. 
