935 
At that time we concluded that none of the first three views had been 
established beyond criticism and that pending a complete solution of the 
matter, the fourth was the only safe one to consider from the standpoint 
of public health in the Tropics. 
Before entering upon a discussion of our continued work on this sub- 
ject, a few communications which were not considered in the first paper 
or which have appeared since, will be reviewed. The most important 
article which deals in part with the pathogenesis of amoebee is that of the 
late Prof. F. Schaudinn, which appeared before our first paper, but which 
was not accessible to us at that time. The other recent papers have 
largely been confirmatory of Schaudinn’s observations. 
The conclusions of Schaudinn which bear upon the subject under discussion 
were based upon the following observations: (1) Amb, always corresponding 
to the description of FE. coli, were found in 20 to 66+ per cent of the stools of 
healthy people (people without clinical manifestations of diarrhea) which he 
examined. (2) These amebe, when injected in the recta of kittens, did not 
produce disease. (3) Ameebe corresponding to his description of EH. histolytica 
were only found in the stools of people with clinical dysentery. (4) These amebie 
when injected into the recta of kittens produced dysentery. (5) “By studying 
fresh sections of the intestine infected with HL. histolytica it is easy to observe 
the ameebe pushing themselves between the epithelial cells of the mucosa.” 
Charles F, Craig, in San Francisco, found F. coli in 65 per cent of the stools 
of healthy people and in 50 per cent of those of patients suffering from diseases 
other than dysentery, and he has informed me verbally that he has found them 
in the stools of 70 per cent of healthy soldiers examined in Manila. His pub- 
lished conclusions confirm and elaborate Schaudinn’s. They are: 
(1) The intestine of man may be infected with two varieties of amebex, a 
pathogenic (KF. dysenteriv) and a non-pathogenic one (H. coli). (2) HB. coli is 
found in 65 per cent of healthy intestines and in 50 per cent of those having 
other diseases, if a saline cathartic is given. (3) These organisms can easily 
be distinguished in both fresh and stained specimens. (4) They differ widely in 
their manner of reproduction. (5) H. dysenteria, when fed in milk or injected 
into the recta of kittens, produce typical amebic ulceration. (6) The same pro- 
cedure (5) with #. coli gives negative results. (7) Similar experiments with 
the intestinal bacteria alone do not produce dysentery. 
It will be noticed that, with the exception of Schaudinn’s statement under sub- 
head No. 5, there is nothing in any of these observations or conclusions which 
has not already been stated many times by different writers. They were also 
summarized in our first publication. The statement of Schaudinn in paragraph 5 
is a most remarkable one and open to criticism. 
We have already dealt extensively with all the points brought out in 
these new investigations,® but as Schaudinn’s work has attracted so much 
attention it seems justifiable again to discuss some of his important 
conclusions, | 
Granting for a moment that amoebe may be present iff the healthy 
colon, how can this fact warrant the conclusion that these amocbe are 
® Loc. cit. 
