8 



DR. BASTIAN ON THE 



tion has deposited phosphates before it reached the boiling-point, 

 and thus has had its acidity lowered*. 



The behaviour of a specimen of urine prepared in the manner 

 above indicated has several times been tested, first under the in- 

 fluence of a lower temperature and afterwards under that of the 

 higher. Thus, to take an example from my note-book, two speci- 

 cimens of a urine whose sp. gr. was 1025, and whose acidity was 

 equivale^at to five minims per ounce of liquor potassae, were kept 

 at a temperature of 80° F. for eight days without undergoing any 

 change ; but within twenty-four hours after they had been trans- 

 ferred to a temperature of 122° F. they were in full fermentation. 



The powerfully stimulating influence of a temperature of 122° F. 

 may also be easily seen in another way. In addition to causing 

 certain fluids to ferment which would otherwise remain barren at 

 ordinary temperatures (77°-86° F.), it shows its influence upon 

 those fluids which will ferment at these lower temperatures, by 

 bringing about such a change with much greater rapidity. 



Ko fluid serves better for showing these relative effects than urine 

 which has been neutralized with liquor potassae before the process 

 of boiling, because, though it will mostly ferment at the lower in- 

 cubating temperatures, it does so with difficulty and only after 

 many days. Thus I have found that a urine whose acidity re- 

 quired ten to twelve minims of liquor potassae per ounce for neu- 

 tralization, would (after such admixture and an ebullition of five 

 minutes' duration) not ferment under 12-15 days, if kept at a 

 temperature of 70°-73° F., though such a change would show 

 itself in 15-30 hours at a temperature of 122° F.f 



In previous paragraphs, when speaking of the degrees of acidity 

 of urme which would permit of its fermenting after ebullition at a 

 temperature of 122° F., I have always referred to its initial aci- 

 dity — its acidity, that is, previous to the process of ebullition, not 



* See p. 53. 



t Whilst such comparisons are so easily to be made by others, and will so 

 plainly show the superior efficacy of a temperature of 122° F. in initiating fer- 

 mentation, one can only marvel at the attempts of Prof. Tyndall and of 

 Dr, Roberts to throw discredit upon my statements on this subject. It is to me 

 surprising that Dr. Roberts (see Proceed, of Royal Soc. No. 176, vol. xxv. p. 456) 

 could have resorted to so unscientific a method of testing the truth of such a 

 simple statement. The method adopted by Prof. Tyndall was perhaps not at all 

 more appropriate,, though, as usual, he is very sparing in his narration of details 

 (Phil. Trans. 1876, Part 1, p. 57), so that it is more difficult to be quite cer- 



in what he did. 



