380 . THE CAUSES OF THE XI 



acid, and others, have been added to the list. I 

 need not tell you that chemistry is an enormous 

 distance from the goal I indicate ; all I wish to 

 point out to you is, that it is by no means safe 

 to say that that goal may not be reached one 

 day. It may be that it is impossible for us 

 to produce the conditions requisite to the origina- 

 tion of life ; but we must speak modestly about 

 the matter, and recollect that Science has put her 

 foot upon the bottom round of the ladder. Truly 

 he would be a bold man who would venture to 

 predict where she will be fifty years hence. 



There is another inquiry which bears indirectly 

 upon this question, and upon which I must say a 

 few words. You are all of you aware of the 

 phenomena of what is called spontaneous genera- 

 tion. Our forefathers, down to the seventeenth 

 century, or thereabouts, all imagined, in perfectly 

 good faith, that certain vegetable and animal 

 forms gave birth, in the process of their decom- 

 position, to insect life. Thus, if you put a piece 

 of meat in the sun, and allowed it to putrefy, they 

 conceived that the grubs which soon began to 

 appear were the result of the action of a power of 

 spontaneous generation which the meat contained. 

 And they could give you receipts for making 

 various animal and vegetable preparations which 

 would produce particular kinds of animals. A 

 very distinguished Italian naturalist, named Redi, 

 took up the question, at a time when everybody 



