258 T^^ Philippine Journal of Science ms 



anyone who takes the trouble to examine the indefinite descrip- 

 tions of the amoeboid organisms employed by these investigators 

 in their experiments. In many instances the author has made 

 no attempt to determine the species with which he has ex- 

 perimented, simply stating that it was an amoeba found in a 

 dysenteric stool or cultivated from such a source and that 

 the amoeba recovered from the experimental animal resem- 

 bled, or was indistinguishable from, the amoeboid organism fed 

 to the animal. Such experiments supply no information as to 

 the species of amoeboid organism associated with the experi- 

 mental dysentery; it does not prove the etiologic relationship of 

 the associated amoeboid organism to the experimental dysentery ; 

 and it vitiates every conclusion drawn by the investigator from 

 his experiments. 



The use of the lower animals for infection experiments is at 

 best only a makeshift, and the application of the results to man 

 is based on the assumption that the microorganism in question 

 behaves in the experimental animal as it would in the human 

 body, an assumption that is not always borne out by the facts. 

 There may exist a more specific objection to the employment of 

 the lower animals for experiments on entamoebic dysentery. 

 Although a number of authors claim to have been successful in 

 infecting animals and in producing dysentery with diff'erent 

 species of amoeba and entamoeba, I have not been able, in a limited 

 number of experiments, to parasitize animals with the pathogenic 

 entamoeba. While these experiments have not been numerous 

 enough to exclude the possibility of infecting animals, they at 

 least indicate that the lower animals are less readily parasitized 

 than man. Every species of animal appears to be parasitized 

 with some species of entamoeba, and dysentery is not uncommon 

 in animals kept in captivity. It is probable that these facts, 

 together with carelessness in identifying species of amoeboid 

 organisms, account for some of these apparently successful infec- 

 tion experiments on animals with amoebee and entamoebse. 



The resort to human experimentation is usually not to be 

 recommended, but in certain infectious diseases of wide geo- 

 graphical distribution and prevalence, or which give rise to 

 devastating epidemics, and of which an accurate knowledge of 

 the etiology or transmission cannot otherwise be obtained, 

 experimental infections of man have been resorted to, and the 

 knowledge thus obtained has enabled medical science to control 



