242 
Intestinal Protozoa of Man 
Liquid Stools. 
The macro,scopical appearance of diarrhoeal stools caused by some of the 
dysenteries in the latter stages and also by the less pathogenic organisms are 
subject to great variation. Three types recently observed, however, are worth 
mentioning. 
In Lamblia infections the stools may be any colour or consistency during 
the encysted stage of the organism and the same applies where small numbers 
of the free flagellate are being passed; but when the free flagellate appears to 
be causing diarrhoea a yellow ochreous motion with streaks or pin point dots 
of mucus without blood is fairly constant. I have noticed similarly coloured 
stools with other conditions. Nevertheless when such stools were associated 
with mucus, Lamblia was generally present. 
During the latter stages of bacillary dysentery a yellow liquid stool smelling 
very offensively is frequently encountered; it is often seen without blood and 
mucus and in patients who have recently passed through a bad attack of 
bacillary dysentery. 
Sometimes one meets with a grey or brownish-grey liquid stool. The 
history generally given is that the patient felt a griping pain in the stomach. 
This was followed by desire to defaecate and the act was accompanied by a 
distressing scalding sensation in the anal canal and round the external 
sphincter, which persisted for some time after the act of defaecation was 
completed. In these cases two or three such stools may be passed daily and 
the condition, if untreated, may persist for two or three days, then passing 
away gradually. If treated with a one ounce dose of magnesium sulphate it 
disappears within 24 hours. In stools from these cases I have almost invariably 
found one or other of the vegetable organisms to be described presently. 
I encountered 15 cases of this kind. 
The naked eye appearances therefore of dysenteric stools are of consider¬ 
able value in guiding one as to the causative organism of an acute diarrhoeal 
condition, but no confident diagnosis can be based on this form of examination 
alone, owing to the great variation of type even in one disease, and the tendency 
of one type to merge into that of another. 
MICROSCOPICAL EXAMINATIONS. 
Dysenteric Stools. In the very early acute stages of bacillary dysentery the 
red blood cell element generally predominates, the white cells being fewer in 
proportion. This stage is rarely seen by the laboratory worker as it generally 
announces the beginning of the attack, is transient, and rapidly gives place 
to the next and most commonly seen phase, where white cells very soon increase 
numerically and cause the red cells to appear more scanty. In typical cases 
there is a marked degeneration of the epithelial and leucocyte cells passed, 
as was pointed out by Bahr (Dysentery in Fiji). But in the earlier stages 
degeneration is not so marked, and moreover, as sometimes a similar degenera¬ 
tion of cells is noticeable in amoebic cases, and in the cells cast off in bilharzia 
