24 



DE. BASTIAN ON THE 



ol 122° F., the two sets of retorts constitute crucial experiments 

 capable of testing the influence of liquor potassae upon the steri- 

 lized urine. 



What I have found to happen almost uniformly in about two 

 hundred of such experiments is this : — If suitable fluids are dealt 

 with — that is, specimens of fresh urine whose acidity before boiling 

 does not require less than 8 minims of liquor potassae per ounce 

 for neutralization, and which do not deposit phosphates on boil- 

 ing — the urine in the control experiments remains clear and appa- 

 rently unaltered for an indefinite time ; whilst where the potash 

 has been allowed to operate upon the sterilized fluid, it becomes 

 turbid, lighter in colour, and swarms with organisms in from 18 to 

 36 hours, on an average. The period with difierent urines is some- 

 times less and sometimes more, though no great prolongation 

 occurs except through some alteration having been brought about 

 in the proper ratio which should exist between the acidity of the 

 boiled fluid and the amount of liquor potassae which is added thereto. 

 Such delays in the occurrence of fermentation were common 

 enough during my earlier trials with this method; but now 

 that I have more carefully studied and ascertained some of their 

 causes, I am generally able to obviate them and ensure the super- 

 vention of fermentation within two or three days*. 



This fermentation of urine to which liquor potassse is added 

 after boiling, unquestionably takes place more readily in a flask 

 plugged with cotton-wool than in a sealed retort from which 

 air has been expelled by boiling. And that the slightly dimi- 

 nished readiness of the fluid to ferment in the airless retort is 

 attributable to the absence of atmospheric oxygen, seems to be 

 confirmed by other experiments now to be recorded, in which 

 an increased readiness to change is exhibited by urine and 

 liquor potassse under the influence of nascent or less-diluted oxy- 

 gen, liberated by electrolysis. 



I have also in two experiments with closed flasks containing 

 urine and ordinary atmospheric airf liberated the liquor potassse 

 after the flask and its contents had been boiled, with the eff'ect of 

 finding fermentation take place several hours earlier than it did 

 * In a few cases this has occurred even when the urine has been heated in the 

 can for 1-2 hours. Thus, I have seen it happen three times where the urine has 

 been boiled for one hour, and once where it has been boiled two hours. With 

 potash added beforehand almost to neutralization, I have twice seen urine fer- 

 ment even after three hours' boiling. 



t The flasks having been hermetically sealed whilst the urine was cold. 



