130 
Entamoeba histolytica 
produced by the nucleus breaking up into chromidial granules, some of which 
passed into the spores, budded off from the peripheral cytoplasm. Darling 
and others have, however, shown that these budding phenomena must be 
regarded as degenerative. 
During the past three years many papers have appeared, the majority ■ 
dealing almost entirely with methods of treatment. Foremost among these 
papers are those by Wenyon and O’Connor in which many of the problems 
connected with E. histolytica and its pathological effects are fairly exhaustively 
treated. Dobell and Jepps, Fantham and Porter, Malins Smith and others 
record observations on the cysts of E. histolytica ; and a long series of papers 
have appeared in French journals. Many of these latter, however, have 
tended to obscure the problem by drawing sweeping conclusions from very 
scanty material. , 
EFFECTS OF VARIOUS SUBSTANCES ON AMOEBAE IN CULTURE. 
The interesting results obtained by Cropper and Drew (1914) by subjecting 
free-living amoebae to the action of various substances led me to make a few 
similar experiments with cultural E. histolytica. 
The substances, whose action I wished to test, were made up to the 
required strength in the culture media; and the wet chamber apparatus, 
already described, was employed. In all cases control slides were used. 
Chlorine. A 12 hours’ subculture was used for making four preparations: 
(A) served as a control, (B-D) were placed in wet chambers with chlorine as 
follows, the number of amoebae on the slides was counted before and after 
incubation at 30 
»° C.: 
Strength of 
Cl employed 
No. of amoebae 
present at start 
No. of amoeba 
present after 
12 hrs incub. 
A. 
Control 
0 
10 
14 
B. 
Chlorine 
0-005 % 
15 
15 
C. 
It 
0-0005 
12 
21 
D. 
>? 
0-0001 
16 
30 
Five other experiments of a similar nature were made, and the results in 
all cases were strictly comparable. It thus appears that chlorine in the strength 
of 1/10,000 stimulates multiplication, whilst 1/2000 has less effect and 1/200 
partially inhibits multiplication. 
Wenyon and O’Connor found that chlorine 1/10,000 has no effect on 
E. histolytica cysts; it is of interest, therefore, that a similar solution stimulates 
propagation in the vegetative forms. 
Tyrosin. Experiments, similar to the above, were made with strengths 
0*2%, 0-5%, 0-01%. The first two solutions stimulated multiplication, 
but the last as well as weaker solutions (0-005 %, 0-0005 %) had no appreci¬ 
able effect. The following protocol relates to one, out of many experiments 
performed: 
