148 SOME MINUTE ANIMAL PARASITES 



Africa, and Egypt, as well as Italy and Greece (to 

 name only a few places among the many affected), all 

 have suffered from the prevalence of dysentery. 



The various controversies that have raged around 

 the causative agents of amoebic dysentery have tended 

 to give the subject a general as well as a scientific in- 

 terest. Losch (1875) was one f the ft 1 " 8 * to describe 

 amoebae occurring in dysentery, and to reproduce 

 the disease by means of them. The first absolute 

 separation of the pathogenic and non - pathogenic 

 amoebae from the human intestine was made by 

 Schaudinn in 1903, who showed that in man there 

 were at least two species of Entamoeba. The one 

 was relatively harmless, and occurred in healthy and 

 diseased individuals alike ; the second occurred only 

 in unhealthy patients, and if its cysts were swallowed 

 dysentery followed. The parasite of dysentery was 

 named Entamceba histolytica by Schaudinn, and the 

 companion but not disease-producing form was 

 termed E. coli. Since Schaudinn's paper, quite a 

 number of pathogenic species have been described, 

 but many of these are now known to be stages in the 

 life-histories of other amoebae, so that one of the most 

 indefatigable workers on the amoebae of dysentery, 

 Darling, now states that there is probably but one 

 pathogenic amoeba. In that opinion he is sup- 

 ported by several other eminent workers and former 

 opponents. Most workers seem to be agreed that 

 the greater number of cases of amoebic dysentery are 

 due to one principal amoeba. They now merely dis- 

 agree as to the exact name whereby it shall be called, 

 the rival names being E. histolytica and E. tetragena. 



