16 DE. BASTIAN ON THE 



experiments which lie undertook with hay-infusion. Small narrow- 

 necked flasks were taken capable of holding nearly 3 oz. of fluid ; 

 and each of these was about half filled with a measured amount of 

 fresh unfiltered urine, whose degree of acidity had been previously 

 ascertained by carefully finding the exact number of minims of 

 the liquor potassae of the ' British Pharmacopoeia ' which were 

 needed to neutralize 1 ounce of it *. Quantities of liquor potassae 

 just sufiicient to neutralize the amount of urine intended for each 

 flask were then enclosed in a number of glass tubes, each of which 

 had a small bulb at one extremity and a similar bulb near the 

 other end, beyond which it was drawn out as a thin proloogation 

 and bent at an obtuse angle. Each of these tubes was charged 

 by heating it in a flame before immersing its open capillary ex- 

 tremity in the requisite quantity of liquor potassse, contained in a 

 minute porcelain capsule. When the whole of the measured 

 amount of alkali had thus been forced into the glass tube, this was in- 

 verted, and its capillary extremity was sealed in the spirit-lamp 

 flame. Its neck was then wrapped round with cotton-wool, and 

 the tube itself was inserted into one of the flasks in such a manner 

 that the cotton-wool might act as a plug thereto, whilst the capil- 

 lary extremity of the tube just touched the bottom of the vessel. 



The flasks being thus charged and arranged, the urine in its 

 altered acid state was boiled over a flame for five minutes. When 

 the fluid had cooled, the tube was pressed down slightly so as to 

 break off its capillary extremity ; and immediately afterwards a 

 flame was applied to the external bulb of the tube, so as to expand 

 its contained air. The measured amount of liquor potassae was 

 thus expelled into the sterilized urine; and the flask was then 

 placed in an incubator and maintained at a temperature of 

 104°-113° F. (40°-45° C.)t. 



Some tentative experiments were made in this manner with 

 fresh urine whose specific gravity varied from 1020 to 1025, and 

 whose acidity was such that 7-15 minims of liquor potassae per 

 ounce were required for neutralization. In nearly every case it 



* In these first experiments the liquor potass^ was delivered from a subcuta- 

 neous injection-syringe, minim by minim when the point of saturation was nearly 

 reached. It may be well to mention that the solution of potash above named 

 has a sp. gr. of 1058, and that it contains 27 grains of caustic potash to the fluid- 

 ounce of water (5"84 per cent.). What I have used has always been purchased 

 from Mr. W. Martindale, of 10 New Cavendish Street, London. 



No higher incubating-temperatures were used in these particular expe- 

 riments. 



