x.] BIOGENESIS AND ABIOGENESIS. 219 



a single biological doctrine ; and I shall try to give some 

 notion of the fruits, both intellectual and practical, which 

 we owe, directly or indirectly, to the working out, by 

 seven generations of patient and laborious investigators, 

 of the thought which arose, more than two centuries 

 ago, in the mind of a sagacious and observant Italian 

 naturalist. 



It is a matter of every-day experience that it is 

 difficult to prevent many articles of food from becoming 

 covered with mould ; that fruit, sound enough to all 

 appearance, often contains grubs at the core ; that meat, 

 left to itself in the air, is apt to putrefy and swarm with 

 maggots. Even ordinary water, if allowed to stand in 

 an open vessel, sooner or later becomes turbid and full 

 of living matter. 



The philosophers of antiquity, interrogated as to the 

 cause of these phenomena, were provided with a ready 

 and a plausible answer. It did not enter their minds 

 even to doubt that these low forms of life were generated 

 in the matters in which they made their appearance. 

 Lucretius, who had drunk deeper of the scientific spirit 

 than any poet of ancient or modern times except Goethe, 

 intends to speak as a philosopher, rather than as a poet, 

 when he writes that "with good reason the earth has 

 gotten the name of mother, since all things are produced 

 out of the earth. And many living creatures, even now, 

 spring out of the earth, taking form by the rains and the 

 heat of the sun." 1 The axiom of ancient science, "that 



1 It is thus that Mr. Munro renders 



" Linquitur, ut merito maternum nomen adepta 

 Terra sit, e terra quo-mam sunt cuncta creata. 

 Multaque mine etiam exsistant animalia terris 

 Imbribus et calido solis concreta vapore." 



De Rerun Natura, lib. v. 793796. 



But would not the meaning of the last line be better rendered "Developed 

 in rain-water and in the warm vapours raised by the sun"? 



