1891.] MICROSCOPICAL JOURNAL. 129 



The Ainnioniacal Fernieiitatioii of Urine.* 



By VERANUS A. MOORE, M. D., 



ASSISTANT IN THE LABORATOKY OF THE BUREAU OF ANIMAL INDU-iTRY, nErAKTMENF OF AGKI- 

 CULTUEK, WASHINGTON, D. C. 



The fact is well known that urine undergoes putrefactive changes 

 when it is allowed to stand for a considerable length of time at the 

 ordinary temperature. In following these in the order of their occur- 

 rence we find that the clear urine first becomes faintly, then heavily 

 clouded, and finally, after several weeks standing, it clears with the 

 formation of a considerable quantity of a grayish, more or less granular 

 sediment. The color of the cleared urine is always several shades 

 darker than that of the fresh liquid. A further examination shows 

 that its acid reaction is converted into an alkaline one simultaneously 

 with the occurrence of the clouded appearance. With this change in 

 its chemical reaction the odor becomes penetrating and ammoniacal in 

 character. The source of the ammonia was explained by the discovery 

 of urea, and later investigations made by Prout showed that the urea 

 was converted into carbonate of ammonia by a process of hydration. 

 By •• ammoniacal fermentation of urine," therefore, is meant that change 

 in urine by which its urea is transformed into carbonate of ammonia. 



The careful chemical investigations that have been made during the 

 past two centuries for the purpose of determining the cause of this 

 transformation of urea into carbonate of ammonia have been negative 

 in their results. • Van Helmont, in the seventeenth century (16S3), 

 believed the cause to be the action of some putrefactive ferment, the 

 exact nature of which he did not know. Pie was supportefl in this 

 theory by other investigators following him. A satisfactory explanation 

 of this phenomena was not made, however, until the time of Pasteur, 

 who showed that the "ammoniacal fermentation" was due to the pres- 

 ence of an organized ferment (micro-organisms). This discovery 

 transferred the line of investigation of this subject from a purely chem- 

 ical to a biological basis. 



The bacteriological investigations of this subject by Pasteur, Van 

 Tieghem, Miquel, Leube, and others during the last thirty years have 

 been so confirmatory that no further evidence is necessary to es- 

 tablish the theory of an organized ferment advanced by Pasteur. I 

 have repeatedly preserved urine for several months in apparently a per- 

 fectly fresh condition by first sterilizing it by discontinuous heating for 

 several days at a temperature of 65° C, after which it was continuously 

 exposed to a temperature most favorable for the development of am- 

 moniacal fermentation ; also by placing it unsterilized in a temperature 

 below that necessary for the development of bacteria. The results ot 

 many carefully-conducted experiments warrant the statement that with- 

 out the development of certain bacteria urine will remain unchanged 

 although subjected to all the other influences necessary for this decom- 

 position. As experiments have shown that the urine within the healthy 

 bladder of people not suflering froin bacterial disease is germ free, it is 

 evident that the organisms producing this decomposition are to be sought 

 for among the external surroundings or in the urethral canal, where 

 they have either entered by accident or where, when once introduced, 



•Proceedings of the American Society of Microscopists, 1890. 



