III. 



THE DOCTRINE OF IMMORTALITY. 



Your Royal' Highnesses! 



To your Royal Highnesses I wish to express my profound 

 and respectful thanks for the honor of your presence, which 

 has for me a great and unforgetable significance. The partici- 

 pation of your Royal Highnesses in to-day's lecture is a high 

 distinction not only for me but for my university, which we 

 gratefully acknowledge. 



Everything living arises only from the living. The phe- 

 nomenon of propagation of animals and of plants has always 

 excited the interest of mankind. The ancients recognized 

 that only living parents could have a living progeny, and it 

 was said "Omne vivum ex vivo." But for a long time the 

 opinion prevailed that life might continually arise anew. We 

 .know now, however, with certainty that a new generation of 

 this kind does not occur, and assume that under present con- 

 ditions a new generation of life is improbable, perhaps impos- 

 sible. We know too little to venture a positive opinion. 

 Schaefer,^^ the gifted physiologist of Edinburgh, has expressed 

 a supposition that new generation still occurs upon our earth 

 and escapes our observation because we do not know the con- 

 ditions which render such generation possible. This is an 

 interesting speculation, but with this possible exception we 

 must attribute to the saying, "omne vivum ex vivo" absolute 

 validity. 



With the progress of our knowledge we have made interest- 

 ing discoveries concerning the manner in which the uninter- 



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