74 PRESIDENTIAL ADDKESS SECTION D. 



Crithidia have been reported from plants, especiaDy from the 

 Euphorbiaceae. 



It may be mentioned here that Protista other than Herj:)eto- 

 monads occur in plants. Thus, amoebae, which, when quiescent, 

 varied from 10^ to 20/t in diameter, have been found by Franchini 

 in the latex of various members of the Euphorbiaceae, 

 Asclepiadaceae, Apocynaceae, Urticacete, Artiocarpeae, and Sapo- 

 taceae. The amoebae are said to be numerous in the latex of 

 Apocynaceae. In some cases, injury to the host plants occurred, 

 in others it was not obvious. The transmission of amoebae from 

 plant to plant is probably by the contaminative method, the 

 infected ftEces of an insect reaching wounded surfaces of plants. 



Spirochaetes also have been found by Laveran and Fran- 

 chini in the latex of Euphorbiaceae. 



Intestinal Flagellates and Their Pathogenic Action in 



DiARRHCEA. 



During the Great War flagellates belonging to the genera 

 Giardia (Lamblia), Trichomonas and Chilomastix were often found 

 in routine faecal examinations, especially of dysenteries. Differ- 

 ence of opinion has occuiTed as to whether these flagellates are 

 pathogenic to man. It must be admitted that they are associated 

 with certain cases of diarrhoea. In the writer's opinion, they are 

 the causal agents of certain forms of enteritis, as cases were 

 known to me personally in which they were the only possible 

 pathogenic organisms present in the disordered intestines. 

 Further, experimental work conducted jointly with Dr. Fantham* 

 in 1916 showed that undoubtedly Giardia (Lamblia) intestinalis 

 (sometimes called G. enterica) was pathogenic to clean laboratory 

 animals (kittens and mice), and also that strains of human Giardia 

 acquired from different sources (Gallipoli and Flanders) varied in 

 virulence in laboratory animals. In South America Escomel 

 1919+ has thoroughly established the pathogenicity of Trichomo- 

 nas hominis, and modifications of his treatment for trichomoniasis 

 have been successfully introduced in South Africa. In connection 

 with experimental work, it must be remembered that one positive 

 result is of more value than a number of negative ones, especially 

 when conducted by persons of experience, who breed their own 

 animals for experimental purposes and, consequently, always l)ave 

 clean " animals at their command. 



Species of Giardia (Lamblia), Trichomonas and Chilomastix 

 occur in other animals, especially rodents. Several species of 

 Giardia have been recorded which may prove viltimately to be 

 varieties of one species. Rodents also may act as natural reser- 

 voirs of the species found in man. The flagellates, in their 

 encysted or rounded forms, can pass unharmed and vmchanged 

 through the bodies of insects, such as flies and cockroaches, and 

 remain infective to man. The insects thus act as mechanical 

 transmitters and distributors of the flagellates. 



* Brif. Med. Journal, July 29, 1916. pp. 139—141. 

 + " La Tricomonosis intestinal." Lima. 1919. 



