juice; but their resistant spores in dried stool, not being affected by this secretion, passed on through the stomach, to develop in the lower bowel. This experiment has been amply confirmed, especially by Wenyon and Darling.* [1]
Histolytica cysts are common in the stools of patients during the latent period of the disease, and also in the stools of normal natives (Hartmann), who thus may be regarded as being carriers of the infection.
The intimate connection of abscess of the liver with dysentery, and the presence of amœbæ in the contents of a large proportion of liver abscesses, are now well-ascertained facts, and constitute a powerful, though by no means conclusive, argument for regarding the amœba as an etiological element, if not the cause, of amœbic dysentery.
There is yet another circumstance in connection with liver abscess which is not without significance. In a large proportion of liver abscesses the usual pyogenic bacteria are absent. This has been proved over and over again. Cultures made with such pus generally remain sterile. It is a very suggestive coincidence that it is just in those forms of suppuratiye hepatitis in which the usual pyogenic organisms are absent that this other parasite is present. Moreover, a liver abscess is not like ordinary abscesses; it has no proper abscess wall. Liver pus is not like pus elsewhere: it contains proportionately very few pus corpuscles; but it contains much tissue debris, many blood cells, and much granular matter. As an abscess it is altogether peculiar. A peculiar effect suggests a peculiar cause.
- ↑ * More recently confirmation of these experiments has been adduced by Walker and Sellards (Phil. Journ. Sci., Aug., 1913). These investigators induced amœbic dysentery in 4 out of 20 persons by administering vegetative amœbæ from dysenteric stools enclosed in gelatin capsules. In the remaining 16 who did not exhibit dysenteric symptoms, cysts containing four nuclei (tetragena cysts) were subsequently found in the stools. Similar experiments with a parallel series of men fed with cultures of several species of free-living amœbæ and also with Entamœba coli produced no symptoms whatever, though cysts typical of these species were, after a short incubation period, found in their stools.
