34 DE. BASTIAN ON THE 



boiling," — when under the word " after " was included a period 

 of fourteen days' exposure " in a warm place." 



The validity or degree of cogency of this statement may, perhaps, 

 be best appreciated by translating it into a symbolic formula : — 

 Let A represent . . . The experimental fluid (urine) . 

 „ cc „ ... The total chemical changes induced by 



boiling it in its acid state. 

 „ a;' „ ... The total chemical changes induced by 



boiling it after neutralization by potash. 

 „ y „ ... The chemical changes which the boiled 



acid fluid may have undergone during 

 the period of probation. 

 ,, s „ ... The influence of potash upon this boiled 



acid fluid after the probation-period. 

 The statement of Dr. Eoberts is, therefore, tantamount to this : — 

 Because A + .r' leads to fermentation, there is no reason why 

 (A. + x-\-y)z should not lead to fermentation. 



That this is no mere fanciful exaggeration of the difierences be- 

 tween experimental conditions which in their totality are assumed 

 to be similar, I will now endeavour briefly to point out. 



{cc and x) In regard to the relative eflects of boiling an organic 

 mixture in an acid and in a neutralized condition, I have elsewhere 

 made the following remarks* : — " When two portions of a solution 

 containing organic matter, the one neutral and the other acid, 

 have been raised to a temperature of 212° F., the organic matter 

 of the one has been injured only by the mere action of heat ; 

 whilst that of the other solution, which has been acidified, has not 

 only had to submit to the deleterious- influence of the high tem- 

 perature, but also to the increased activity of the acid at this 

 temperature. The result would be, that the amount of difference 

 existing between the two solutions before they had been heatedf 

 would be found more or less increased after they had been ex- 

 posed to the high temperature, in direct proportion to the increase 

 in intensity of the action of the acid produced by such high tem- 

 perature. "What we know concerning the precipitation of albu- 

 men in urine is quite in harmony with this view. When albumen 

 is present, and the fluid has an alkaline reaction, mere boiling does 

 not cause its precipitation — though, if the reaction is acid, the 



* ' Beginnings of Life,' 1872, vol. i. p. 372. 

 t See p. 13 of this memoir. 



