48 



DR. BASTIAN ON THE 



Before we can safely adopt the first two-sided alternative as 

 the explanation of my results, we must be thoroughly assured 

 that the second equally two-sided alternative is out of the ques- 

 tion. It is thus only that we can advance towards the truth in 

 this inquiry. The correct interpretation will be arrived at per 

 viam exclusionis. It must, from the very nature of the inquiry, 

 rest upon inference rather than demonstration. 



Further light may subsequently be forthcoming in favour of 

 or against the explanation (h), of a survival with life-renewal of 

 germs ; but at present it seems to me to stand in this way : — 



For. 



The difficulty in believing that 

 living matter can really have origi- 

 nated de novo in these experiments. 



Against. 



1. The proved inhibitory effect in 

 my experiments of even a slight ex- 

 cess of potash, though previously 

 unheated ferment-organisms vrill mul- 

 tiply in a strongly alkaline urine (7 

 of urine to 1 part of liquor po- 

 tassse) vehen exposed to the same tem- 

 perature of 122° F. 



2. All the previous evidence vrhich 

 led to the generally accepted con- 

 clusion that ferment-organisms and 

 their germs are killed in acid fluids 

 at 100° C. 



3. The absence of any independent 

 reason for doubting the validity of 

 this conclusion — other than that 

 cited in the left-hand column. 



So also may further light subsequently be forthcoming in favour 

 of or against the explanation (a), of the death and de novo produc- 

 tion of germs in my experiments ; but at present the principal 

 considerations for and against this view appear to be as follows : — 



ing, would bring the whole inner surface into contact with the heated acid 

 fluid. This could not be well done in M. Pasteur's more complicated appa- 

 ratus ; and, as I have already pointed out (p. 20, note *), there has been another 

 important difference in our mode of procedure. Hitherto our standard of neu- 

 trality has been different ; and it seems possible that the " neutrahty " to which 

 M. Pasteur reduced his fluid even after boiling (by means of potash) may have 

 been for me a condition of " acidity " equivalent to about 7 minims of liquor 

 potass8e per ounce. Again, in the experiments which I made with Prof. Burdon 

 Sanderson (' Nature,' Jan. 9, 1873, vol. vii. p. 180), the superheating of the vessels 

 was foimd to have no influence whatever over the results. In view of these 

 complications some careful work will be required before I can speak further 

 in regard to this last interpretation by M. Pasteur. — Sept. 24, 1877. 



