256 The Philippine Journal of Science wis 



A number of other authors, notably Schaudinn (1903), Craig 

 (1905), Vedder (1906), Werner (1908), Hartmann (1908), 

 Whitmore (1911), and Darling (1912), have each arrived at some 

 of these conclusions. 



The investigation which forms the subject of this paper has 

 been undertaken to test experimentally the validity of these 

 conclusions and to obtain such other information as may be 

 possible concerning the etiology and endemiology of entamoebic 

 dysentery. 



Tw^o general methods of experimentation are available for 

 determining the specific identity of microorganisms and their 

 etiologic relation to a disease; namely, (a) the study of their 

 immunity reactions and (b) the experimental infection of 

 animals. 



The application of immunity reactions to the determination 

 of species of amoebae and of their relations to entamoebic dysentery 

 has been attempted by Sellards (1911). So far as this method 

 was found applicable, it confirmed the conclusions of the mor- 

 phological study. However, this method of experimentation 

 was found to have certain serious limitations as applied to these 

 organisms. The immunity reactions to protozoa have in general 

 been found to be of a low grade, and those to amoeboid organisms 

 present no exception to the general rule. A second and more 

 serious obstacle to the application of these reactions to the 

 problem under consideration is the fact that it has been found 

 impossible to cultivate the parasitic entamoebse on artificial media 

 or even to keep them alive outside of the body of their host long 

 enough to test the immunity reactions against them. It is 

 further to be noted that immunity reactions can at most only 

 supply indirect evidence of the specific identity of a microor- 

 ganism and its etiologic relation to a disease. 



The experimental infection of animals with amoeboid organ- 

 isms has already been employed very extensively in attempts 

 to prove their etiologic relation to dysentery. Dysentery has 

 been produced by a number of investigators * in a certain pro- 



"Loesch (1875), Hlava (1877), Kartulis (1889), Kovacs (1892), Quincke 

 and Roos (1893), Kreuse and Pasquale (1893), Zancoral (1893), Roos 

 (1894), Gasser (1895), Fijardo (1896), Strong and Musgrave (1900), 

 Harris (1901), Jaeger (1901), Ucke (1902), Huber (1903), Schaudinn 

 (1903), Craig (1905), Hartmann (1908), Werner (1908), Darling (1912), 

 Fantham (1912), Franchini (1912), Hartmann (1912), Wellman (1912), 

 Wenyon (1912). 



