152 Dr. H. C. Bastian on the [June 15, 



latter fluid, however, is for several reasons more suitable than hay- 

 infusion for trymg such experiments. 



Several trials made with urine in this apparatus showed that its fer- 

 mentabilitj was just as much increased by adding boiled hquor potassse 

 after the urine had been boiled in the acid state, as by adding the alkali 

 previous to the process of ebulhtion. Such a result was therefore quite 

 opposed to the first interpretation as to the cause of the increased 

 fermentability of neutralized urine. 



The definite overthrow or establishment of this interpretation was so 

 important that it seemed desirable to try such experiments again by some 

 more rigid and certain method. The author, therefore, devised a new 

 mode of experimentation in which sealed retorts replaced the flasks 

 plugged with cotton-wool, and in which the contents of the enclosed 

 liquor-potassse tubes could be more effectually heated. 



It ^ was first of all ascertained that accurately neutraHzed urine boiled 

 in a retort and sealed whilst boiling would ferment in a day or two if 

 kept at a temperature of 122^ F. * 



This fact having been estabhshed, other retorts were charged with a 

 measured amount of urine, and also with a small glass tube containing 

 liquor potassse in quantity almost sufficient to neutrahze the urine 

 employed t. The glass tubes containing the hquor potass^ had been 

 drawn out at one end, sealed and then immersed in boiHng water for 

 different periods before introducing them into the retorts. After each 



retort had been charged with urine and a liquor-potass as tube, its neck 

 was di'a^Ti out to a capillary point, the urine was boiled, and the retort 

 was hermetically sealed before ebullition had ceased. Thus closed, the 



* Tliough the boiled urine will ferment in retorts from which the air has been 

 expelled by boiiuig, it will undergo this change more quickly if it is in the presence of 

 purified or sterilized air. In the experiments now about to be described, however, it 

 was much more convenient to use airless retorts. 



t As a slight excess in the amount of liquor potassse has been proved to have a most 

 restrictive influence when dealing with urine, it was found safer in these experiments 

 not to provide liquor potassse sufficient for full neutralization. Many details on thi^ 

 subject are given in the memoir itself. 



