CONDITIONS FAVOUEING FERMENTATION. 



21 



Fig. 5. 



to facilitate this part of the process, I have made use of a lipped 



measure (fig. 5) having a rather narrow 



orifice, which can be easily covered by 



the thumb so as to allow its contents to 



be shaken for the thorough admixture 



of each quantity of liquor potassse with 



the urine to which it has been added. 

 These experiments have hitherto 



been exclusively conducted with my 



own urine ; and I have generally found 

 that which was passed in the morning 

 before breakfast very suitable for use. 

 Til is fluid has remained clear after 

 boiling, no phosphates being deposited 

 during the process ; its acidity has 

 usually been neutralized by 10-14 

 minims of liquor potassse per ounce ; 

 and its specific gravity has varied from 

 1020 to 1025. 



When the acidity of the urine with 

 which experiment is to be made has 

 thus been accurately determined, one 

 can easily settle which set of the Lipped measure for^xlmixturo 

 already prepared liquor-potassse tubes ^^ potash. 



it will be most convenient to employ. I have generally made use 

 of about 1-1| ounce of urine for each experiment, and, after 



tass« in an ounce of distilled water may be recognized by the previously red- 

 dened litmus paper, whilst 5 of a minim in the same quantity of distilled water 

 may be detected by the yellow turmeric paper. The latter, though less delicate, 

 gives the most certain indication, especially when a drop of the fluid to be tested 

 is allowed to fall on dry turmeric paper. As the fluid is absorbed by this 

 partly bibulous paper, a faint brown circle is seen for a moment or two when 

 the fluid is very faintly altalijie. The importance of such details as this will bo 

 obvious when I say that, last July, urine which I tested in M. Pasteur's labo- 

 ratory and found to have an acidity equivalent to 7^ minims of liquor potasses 

 per ounce, was pronounced by M. Pasteur to be " legerement alcalin," according 

 to the indications of a slightly reddened litmus paper recently used in his labo- 

 ratory. This was a most surprising difference ; and I cannot say yet how far our 

 very different indications hitherto as to degrees of acidity and alkalinity may 

 account for some of the discrepancies between the results of M. Pasteur and 

 myself in the performance of these urine and liquor-potass^ experiments (see 

 Note 1, p. 180, of the 'Coraptes Rendus' for July 23, 1877, where M. Pasteur 

 has also something to say on the same subject). — Sept. 1877. 



