AMGEB^E IN RELATION TO DYSENTERY 747 



origin of dysentery and while he has had the support of a number of observers 

 (Councilman, Lafleur and others), he has been opposed by Tancarat, Quincke 

 and Roos, Massintin, Wilson, and others. 



The following facts have been urged against the view that dysentery may be caused 

 by an amoeba. 



(1) Amoebae are not constantly found in persons suffering from dysentery. 

 Laveran only found amoebae in one case of dysentery out of ten examined by 



him, Krause and Pasquale in 10 out of 35 cases, Grasser in 45 out of 105 cases, the 

 author in 2 out of 12 cases, Kartulis in 18 out of 35 cases, etc. 



(2) Amoebae are sometimes found in diseases other than dysentery as well as in 

 healthy persons. 



Quincke and Roos examined the stools of a number of healthy persons after they 

 had taken a dose of a purgative and found amoebae in 9 out of 21 cases : Grasser, 

 Wilson, Besson have also found amoebae in the excreta of healthy men. Sanarelli 

 found amoebae in considerable numbers in the intestines of guinea-pigs which had 

 died of enteritis following the ingestion of cholera toxin, and in his opinion amoebae 

 are able to multiply in the intestine of these animals in all cases of toxic enteritis. 



(3) Chantemesse, Shiga, and others have described a bacillus which is obviously 

 the cause of a large number of cases of dysentery (Chap. XX.). 



Recent investigations, however, have solved this very vexed question of 

 the aetiology of dysentery by showing that the clinical term Dysentery includes 

 two distinct diseases. 



(1) An acute, epidemic disease, occurring especially in temperate climates 

 and caused by the bacillus of Chantemesse-Shiga. 



(2) A chronic, endemic disease prevalent in warm climates, sometimes 

 accompanied by abscess of the liver and caused by an amoeba. 



It should be mentioned that in the human intestine two species of amoeba may 

 be encountered : 



(1) Amoeba coli, non-pathogenic and frequently present in healthy persons; 



(2) Entamoeba histolytica, or Amoeba dysenterica, a pathogenic organism and the 



cause of endemic dysentery (Schaudinn, Jurgens) ; 



and the differences of opinion which are found in the works of some writers are to 

 be explained on the ground of a confusion of these two species one with another. 



But though dysentery is generally due to one or other of the organisms 

 mentioned there would appear to be a limited number of cases in which the 

 symptoms are due to other organisms.. Thus, cases have been recorded in 

 Germany, Russia and warm countries in which the infecting agent is a 

 parasite known as Balantidium coli (vide infra), and other cases have been 

 described in which the following parasites appeared to be the cause of the 

 symptoms : a Spirillum (Le Dantec at Bordeaux), Chilodon dentatus (Guiart), 

 Trichomonas intestinalis (Castellani, Billet), the Hcematozoon of Laveran 

 (Billet, Marchoux), Bilharzia hcematobia (Firket, Letulle, etc.). 



Microscopical appearance. 



1. The Amoeba coli (Entamoeba coli of Schaudinn) closely resembles the 

 Amoeba princeps and even more closely Amoeba pelaqinia (Mereschowsky), 

 another protozoon of very wide distribution outside the body. 



In the stools it occurs as a clear, slightly greyish, rounded or elliptical 

 mass of protoplasm measuring 15-60//, in diameter, and as a rule only pro- 

 truding a single pseudopodium. It consists of a slightly granular endosarc 

 surrounded by a clear ectosarc. The endosarc contains a rounded nucleus 

 and one or more highly contractile vacuoles, and in addition there will usually 

 be seen a number of foreign bodies (bacteria, blood cells, etc.) which have 

 been absorbed by the amoeba. The movements of the protozoon are very 

 limited and exceedingly slow, so that it does not travel its own length in a 

 minute. Reproduction takes place by fission, the parasite dividing into two 



