— i 5 o — 
generative changes in trophozoites from tetra gêna -dysentery in 
man hâve been not uncommonly observed. 
When a person is infected with E. tetragena, and trophozoites 
first make their appearance in the stools, they display certain 
familiar features. The trophozoites are large, the nucléus relati- 
vely small, while the cytoplasm is always free from chromidia 
(crystalloidal substance? Chatton), and cysts are never seen. If 
the individual is energetically or suocessfully treated, or in any 
case recovers from the infection, trophozoites disappear from the 
stools and the infection is at an end. 
It is very important that the morphological characters of the 
nucléus in such a case be noted. If wet-fixed préparations are 
made and stained with haematoxylin, it may be noted that sligh- 
tly different pictures may be obtained by using different fixati- 
ves and different modifications of haematoxylin. For example, if 
Schaudinn’s fluid is used, and iron haematoxylin, or iron hae- 
matein, the picture is on the whole like that figured by Wer- 
ner (i) for E. histolytica. The centriole is small and stains faintly 
and the peripheral chromatin while présent, is often not pro- 
nounced in amount nor in intensity of staining. The karyosome 
may be invisible or appear as a very faint cloudy ring. 
If Zenker’s or Flemming’s solution be used instead, and 
Mallory’s phosphotungstic acid haematoxylin be used, a slight- 
ly different picture is obtained, for in the latter case the centriole 
is more densely stained, tliere frequently appears to be more peri¬ 
pheral chromatin often in round granules and staining intensely; 
the karyosome, while faint, is usually very definitely stained. 
A constant technique, therefore, must be used when comparing 
préparations from various sources for diagnosis or study. The 
writer recommends fixation in Zenker’s fluid, diluted one-fourth 
or one-eighth, or in Flemming’s solution, staining in phospho¬ 
tungstic haematoxylin and differentiating with weak potassium 
permanganate solution. 
If one encounters a return case of entamœbic dysentery, or a 
prolonged untreated case, one may find associated with, or ins¬ 
tead of the large trophozoites, described above, a génération 
of trophozoites usually smaller in size. These may be found in 
typical dyenteric stools with blood and mucus or in stools contai- 
(i) Beiheft u Archiv f. Schiffs u. Tropcnkrankheiten, 1908. 
