84 "Retrograde Circiilation of Calcium" 



These analytic results show that the proportions of calcium and 

 volatile fatty acids are practically uniform in the urine of the same 

 person, under normal conditions and during the polyuria produced 

 by the drinking of an abundance of water. The rectal absorption of 

 calcium salts of volatile fatty acids produces a simultaneous, rapid, 

 and striking increase of both calcium and fatty acid in the urine. " 

 The small increase of volatile fatty acid in the urine above normal or 

 above the polyuria potatoria, after rectal injection of ammonium 

 butyrate, is not due to direct passage into the urine of the absorbed 

 fatty acids in combination with ammonia. This small increase may 

 be explained by a formation of calcium salts through the solvent 

 action of the ammonium butyrate sol. on the carbonates and phos- 

 phates of calcium that occur abundantly in every feces, as a simple 

 and direct experiment on feces shows (similar to the one mentioned 

 before). Anexact investigation of the nature of the volatile fatty 

 acids in the urines of persons submitted to the action of rectal injec- 

 tions shows that butyric or acetic acid predominates in the urine 

 when rectal injection of a salt of one or the other of these acids 

 is used. Finally, by a suitable mixture of both kinds of salts (am- 

 monium and calcium), it is possible to obtain simultaneously the 

 polyuria, the calcariuria and the lipaciduria, as they occur in diabetes. 

 The polyuria is induced by the salt that yields urea (17). 



General deductions. The foregoing data show that calcium, 

 and with it volatile fatty acids, describe a very interesting " retro- 

 grade circulation" in the human body, the biological mechanism of 

 which has not hitherto been demonstrated. The calcium and vola- 

 tile fatty acids in urine are generally considered final products or 

 residues of tissue metabolism. These investigations demonstrate that 

 the presence of most of each substance in the urine may be explained 

 by the " retrograde circulation of the calcium," which is initiated by 

 intestinal putref action. 



Although in the present State of our knowledge of this subject, it 

 is impossible to say that all the calcium and all the volatile fatty 

 acids of the urine have the exclusive intestinal and bacterial origin 

 above mentioned, nevertheless the data at band Warrant the convic- 

 tion, already expressed, that most of each arises in the manner sug- 



