130 III THE EVOLUTION OF VIRUSES 



administration of polished rice or wheat. Among the former group of 

 diet, wheat bran was found the most effective. This effect was not 

 destroyed even when the bran was exposed to 120X. for 15 min., indi- 

 cating that the effect was not attributable to phage contained in the 

 diet, because no phage is so stable as to stand such high temperature. 



The conclusion that phage present in the feces is produced by the 

 chicken itself is supported strongly by the fact that phage was found 

 in a variety of organs of the chicken, such as brain, liver, kidney, and 

 lung ; especially abundantly in mucous membranes of intestines. It is, 

 however, a note-worthy fact that the demonstration of phage in organs 

 was possible not only with chickens but also with mice, in whose feces 

 phage could scarcely be found. Mackinley (3) likewise isolated phage 

 from the organs of man and various other animals, and Tempe and 

 Uhlhorn (4) from the blood of guinea-pigs and rabbits. These facts 

 indicate that the presence of phage in animal organs is a general 

 feature. It is strange to say, however, that usually phage cannot be 

 found in the feces of animals such as mice, guinea-pigs, and rabbits, 

 unlike in chicken feces. What is the reason then why phage is demo- 

 strated so readily in the feces of chickens while not in those of many 

 other animals ? 



As above stated, the phages given by the mouth to the chickens 

 were mostly inactivated in the alimentary tract, only their extremely 

 small portion being excreted with the feces, while, on the other hand, 

 it was confirmed that the degree of the inactivation in the alimentary 

 tract was much greater in guinea-pigs than in chickens. In guinea-pigs 

 usually the complete inactivation occurred and no phage was excreted 

 in the feces even if extremely large amounts of phage were fed. This 

 suggests that the absence of phage in the feces of the latter animals 

 might be attributed to the complete inactivation of the phage which 

 might be excreted by the organs into the alimentary tract. 



This deduction is further supported by the following fact : Guinea- 

 pigs given with castor-oil excreted phage markedly in their diarrhoeatic 

 feces, showing that the phage produced by organs was excreted without 

 being inactivated in the intestine owing to the diarrhoea. Besides 

 castor oil, some chemicals such as ethyl alcohol and sodium bicarbonate 

 could occasionally exhibit the same effect, but the phage demonstration 

 in the feces was possible only when diarrhoea occurred. 



It is said that phage was for the first time isolated from human 

 feces suffering from dysentery. This might likewise depend upon the 

 diarrhoea whicli prevented the inactivation of the phage. The phage 

 isolated from dysentery patients is likely to be thought as being specific 

 to the dysentery bacillus, but such appears not the case, generally no 

 peculiarity being found in the specificity of the phage isolated from the 



