254 INFECTIONS OF THE DIGESTIVE TRACT 



tration, when the influence on the nervous system be- 

 came distinct and led to irritability, headache, flight of 

 ideas, etc. It should be noted that the quantity of indol 

 administered in this case was probably in excess of any 

 amount that would be absorbed from the intestine, even 

 in the most pronounced pathological condition. It 

 would not, however, be safe to infer from this that smaller 

 doses would have been harmless ; for while such smaller 

 doses might have produced little or no effect if given 

 during a few days to a normal person, it is not unlikely 

 that its long-continued administration would have led 

 to symptoms. But here again it must be emphasized 

 that the significance of indol absorption for the organism 

 must depend largely on the ability of the organism to 

 quickly oxidize and pair the indol to indoxyl-potas- 

 sium-sulphate. 



The idea that the circulation of free indol in the blood 

 may act in a depressing manner upon muscular struc- 

 tures is suggested by the rapid muscle fatigue which 

 comes on in some persons who have suffered for a long 

 period of time from a high grade of indicanuria. It is 

 also suggested by the observations which I have made 

 that moderate doses of indol by the stomach may be 

 followed in normal persons by a sense of muscle fatigue, 

 which has worn off rapidly on prolonged exercise. Pro- 

 fessor Fred. S. Lee of Columbia University was so kind 

 as to undertake experiments upon the muscles of cold- 

 blooded animals and mammals with a view to determining 

 the influence of indol upon the onset of muscle fatigue. 

 His results are expressed in the f ollowing notes : 



