3l0 THE CANADIAN NATURALIST. [Sept. 



capacity. I shall not presume to attempt a panoramic survey of 

 the world of Science, nor even to give a sketch of what is doing in 

 the one great province of Biology, with some portions of which my 

 ordinary occupations render me familar. But I shall endeavour 

 to put before you the history of the rise and progress of 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 thoughts which arose, more than two centuries 

 ao^o. in the mind of a sao;aciaus 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 v/hich 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.*' The axiom 



of ancient science, " that the corruption of one thing is the birth 



of another," had its popular embodiment in the notion that a seed 



dies before the young plant springs from it ; a belief so widespread 



and so fixed, that St. Paul appeals to it in one of the most splendid 



outbursts of his fervid eloquence : — " Thou fool, that which thou 



sowest is not quickened, except it die." (1 Corinthians, xv. 36.) 



The proposition that life may, and does, proceed from that which 



has no life, then, was held alike by the philosophers, the poets, and 



the people of the most enlightened nations, eighteen hundred years 



a.<^o • and it remained the accepted doctrine of learned and 



unlearned Europe, through the IMiddle Ages down even to the 



seventeenth century. 



It is commonly counted among the many merit>- of our great 



