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OBSERVATIONS ON ENTAMOEBA GINGIVALI8 
FROM THE HUMAN MOUTH, WITH A NOTE 
ON THE TRICHOMONAD FLAGELLATE TE- 
TRATRICH0M0NA8 BUCCALI8 n. sp. 
By T. GOODEY, D.Sc., 
Protozoologist, Research Laboratory in Agricidtural Zoology, 
Unnvrsity of Birmingham, 
AND A. W. WELLINGS, M.D.S., L.D.S., 
Lecturer in Dental Histology and Pathology, University of 
Birmingham. 
(With Plates XX—XXII.) 
CONTENTS 
Introduction 
Methods . 
(a) Observations on the living organism 
(6) Fixed and stained material 
Morphology ...... 
(n) The living amoeba 
(b) The stained organism 
(c) The food of E. gingivalif: . 
Description of cases ..... 
Conclusion ...... 
A note on the trichomonad flagellate Tetrntrirhowoi 
References ...... 
Explanation of Plates .... 
ax hvrcnli. 
n. sp 
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Introduction. 
The claim made for the first time by Barrett and Smith (1914 o) 
some two years and a half ago, that the causative agent of Pyorrhoea 
Alveolaris is the Entamoeba gingivalis led the writers to enquire into 
the question ; the results of which enquiry are set forth in the following 
paper. 
