944 
that no infection could be produced by abdominal inoculation into 
animals on occasions when the bacteria were destroyed by Pfeiffer’s 
phenomenon. In the more recent work which we have just been dis- 
cussing, in cases in which the infection of either the liver or abdomen 
was aided by previously infecting the animal with the symbiotic bac- 
terium (B. typhosus), it was found that the best results were obtained 
if the ameebic inoculation was performed at a no greater interval than 
twenty-four to sixty hours after the preliminary bacterial infection. 
Positive results were less certain if several days were allowed to elapse 
between the inoculations, than when healthy animals were used. 
These observations lead so directly to a discussion of the interesting 
problem of immunity in general against parasitic infections, which we 
are not prepared to undertake at the present time, that we here only 
wish to record these preliminary observations on the influence of a de- 
stroyed bacterial symbiosis upon the parasitism of the associated amebe. 
THE PRODUCTION OF LESIONS, 
Having established the fact of the true parasitism of amcebe, not only’ 
in the production of the intestinal lesions, but also in the liver and other 
tissues of the body, it becomes important to examine carefully the 
manner in which these lesions are produced. 
Practically all which has been written upon this subject deals with 
intestinal infection, and the majority, of writers consider that the 
amcebee penetrate the mucosa in a mechanical manner and reach the 
deeper structures, where lesions begin. Schaudinn also expresses this 
opinion and describes how, in fresh sections of the intestine, he has 
seen “H. histolytica” penetrating between the epithelial cells of the 
mucosa by means of the pseudopodia thrown out by the dense, tenacious 
ectosare. Our observations lead us to differ not only with Schaudinn’s 
interpretation of the conditions but also with his conclusions. 
In our studies of sections from many cases of amoebiasis we have 
never as yet seen any evidence of intestinal infection in which the 
mucosa was intact. The primary lesion is always of the mucous mem- 
brane and the epithelial cells always suffer. Of course, because of the 
extensive undermining which often occurs in the submucosa, one can 
find areas in which the mucosa is intact over deeper lesions for consider- 
able areas, but lesions of this kind are not early ones, and when exam- 
ination reveals the point of entrance, in that portion a diseased patch 
of mucosa will always be found. Indeed, we have been so fortunate as 
to observe lesions so close to their initial stage that only the mucosa 
showed changes.'” 
"These have been described by Woolley and Musgrave in Publications of the 
Biological and Serum Laboratories, Bureau of Government Laboratories, Manila 
(1905), No. 32, and also in J. Am. Meds Ass. (1905), 45, 1371. 
—_— 
~~ 
owe 
