46 DR. BASTIAN ON THE 



3. Control Experiment. 



Boil an ounce of the same acid urine in a small flask whose neck is plugged 

 with cotton-wool for 10". 



When fluid has cooled remove cotton plug for an instant, and add one minim 

 of the same turbid fluid not previously heated. Quickly replace cotton plug 

 and transfer to incubator at 122° F. 



Besult. — Well-marked turbidity and swarms of Bacilli in 18-24 hours. 



Such experiments have invariably given the same results. 

 Twelve trials were made with a urine of 1030 sp. gr., whose 

 acidity was equal to 10 minims of liquor potassse per ounce ; and 

 nine trials were made with a urine whose acidity equalled 25 

 minims per ounce, and whose sp. gr. was 1030, 



These experiments are of much interest, because they show in 

 a most decisive manner that the mere neutrality or slight alka- 

 linity of the medium in which the ferment-organisms are heated 

 is quite unable to preserve them from the destructive influence of 

 a temperature of 100° C* They show also that Bacilli, not pre- 

 viously boiled, develop and multiply with great freedom even in 

 very highly acid urine. Other experiments have also shown that 

 these organisms can develop in strongly alkaline urine (see p. 48). 

 Both these latter facts will help to throw light upon subsequent 

 interpretations. 



Meanwhile the perfectly proved conclusion at which we have 

 arrived is this : — M. Pasteur's explanation of the fertility of neu- 

 tral or faintly alkaline fluids is erroneous; if ferment-organisms 

 and their germs are killed at 100° C. in acid fluids they are also 

 killed in neutral fluids at 100° C. The explanation of the fer- 

 tility of these neutral fluids, therefore, after boiling, both in the 

 hands of M. Pasteur and of other experimenters, still remains to 

 be discovered. 



The one fact, indeed, to be recognized is, that the addition 

 of liquor potassse in proper quantity to a suitable acid infusion 

 either hefore or after boiling will, under the influence of certain 



fully set forth in ' Nature', Aug. 2, 1877, p. 276. It would appear that, subse- 

 quent to the date of his challenge, M. Pasteur must have discovered that his 

 original explanation was erroneous, and that whilst acting in strict comphance 

 with its terms the superheated liquor potasste would induce fertility, as I had 

 said. No declaration to this effect, however, was made in my presence to the 

 Commission ; nor did the Commission itself make any such announcement to 

 me.— Sept. 24, 1877. 



* Confirmatory of other experiments which I made in 1873 ('Proceed, of 

 Royal Soc,' No. 145, vol, xxi. p. 325). 



