410 VETERINARY BACTERIOLOGY 



but the frequent occurrence of the organisms of this genus in the 

 intestines of the lower animals, and the possibility of confusing 

 the adult stage with certain developmental stages of the sporozoa, 

 renders a discussion of these forms advisable in a veterinary text. 

 The possibility of any of the forms being pathogenic for lower 

 animals has not been sufficiently investigated. 



THE GENUS ENTAMOEBA 



The normal inhabitant of the intestinal tract of man was 

 first known as Amoeba coli. Later, Schaudinn renamed it Enta- 

 mceba coli, and gave the name Entamceba histolytica to the patho- 

 genic type associated with the amebic dysentery. The genus 

 Entamoeba was differentiated from Amoeba by the absence of a 

 contractile vacuole and the formation of multinucleated cysts. 



Authorities differ greatly in their estimates of the number of 

 species of amebae present in the intestines of man. The best 

 classification, and the one most commonly used now, is that of 

 Schaudinn. He recognizes two species at least one a normal 

 non-pathogenic form, Entamoeba coli, and one pathogenic for man, 

 Entamoeba histolytica. More recently Hartmann and others have 

 described a third species, E. tetragena, and Koidsumi a fourth, 

 E. nipponica, both from cases of dysentery. The possibility of 

 any of the dysenteries of the lower animals being caused by amebse 

 has not been sufficiently studied. It was at one time believed that 

 certain diseases of turkeys and other fowls, particularly entero- 

 hepatitis, were caused by an ameba termed Amoeba meleagridis, but 

 this has been shown to be but a developmental stage in the life 

 history of a Coccidium. 



Examination of Living Amebce. The amebae may be examined 

 in the stools in a living condition, by placing a portion of the liquid, 

 or a bit of the solider material moistened with physiological 

 salt solution on a slide, and pressing down a cover-glass not too 

 firmly. Craig advises the use of a very weak solution of neutral 

 red to stain the living organisms when they are not present in 

 too great numbers. For the specific determination of the amebae 

 present an examination of this kind is frequently all that is neces- 

 sary. The slide must be maintained at about blood heat in order 

 to detect motility. 



