434 THE BEGINNINGS OF LIFE. 



compared with those which favour their induction in 

 the outside world), the chances become far less when 

 still higher temperatures are made use of, with or 

 without longer periods of exposure. And, ultimately, 

 a limit must be attained, at which the degrading in- 

 fluence of heat produces effects that suffice to render 

 the experimental vessel a dreary and lifeless tomb, in 

 which no living thing can subsequently arise. The 

 transition from the not-living to the living, is an 

 ascent in molecular complexity which may not be 

 possible under such conditions where the much-altered 

 matter exists, though shorn of its finer virtues. 



' Nee pent in tanto quicquam (mihi credite) mundo, 

 Sed variat, faciemque novat : nascique vocatur, 

 Incipere esse aliud, quam quod fuit ante ; morique, 

 Definere illud idem.' 



Although no additional evidence is actually required 

 to prove that living matter can and does arise de novo, 

 still my own experiments, and those of others, in 

 which very much higher temperatures have been re- 

 sorted to, and successful results have yet been obtained, 

 ought to be cited, because of the great additional surety 

 which they supply that no pre-existing living matter 

 was left within the experimental flasks. 



In 1851, Prof. Mantegazza a , of Pavia, introduced a 

 decoction of lettuce into a strong glass tube, and then 

 hermetically sealed it in the flame of a lamp. One- 



1 ' Giornal dell R. Istituto Lombardo.' Exp. iii. 



