ORIGINATION OF LIVING BEINGS 57 



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 generation. 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 decomposition, 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 con- 

 tained. 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 believed in it ; among others our 

 own great Harvey, the discoverer of the circulation of the 

 blood. You will constantly find his name quoted, however, 

 as an opponent of the doctrine of spontaneous generation ; 

 but the fact is, and you will see it if you will take the trouble 

 to look into his works, Harvey believed it as profoundly as 

 any man of his time ; but he happened to enunciate a very 

 curious proposition that every living thing came from an 

 egg ; he did not mean to use the word in the sense in which 

 we now employ it, he only meant to say that every living 

 thing originated in a little rounded particle of organized 

 substance ; and it is from this circumstance, probably, 

 that the notion of Harvey having opposed the doctrine 

 originated. Then came Redi, and he proceeded to upset 

 the doctrine in a very simple manner. He merely covered 

 the piece of meat with some very fine gauze, and then he 

 exposed it to the same conditions. The result of this was 

 that no grubs or insects were produced ; he proved that 

 the grubs originated from the insects who came and 

 deposited their eggs in the meat, and that they were 

 hatched by the heat of the sun. By this kind of inquiry 

 he thoroughly upset the doctrine of spontaneous generation, 

 for his time at least. 



Then came the discovery and application of the micro- 

 scope to scientific inquiries, which showed to naturalists 

 that besides the organisms which they already knew as 

 living beings and plants, there were an immense number 



