&quot; THE ORIGIN OF SPECIES.&quot; 81 



views, and illustrate them with a variety of independently 

 selected facts. Of this second, Mr. Darwin wrote as 

 follows : 



You must let me express my admiration at this most able 

 essay, and I hope to Ciod it will be largely read, for it must 

 produce a great effect ... I have not u criticism to make, 

 for I object to not a word ; and I admire all, so that I cannot 

 pick out one part as better than the rest. It is all so well 

 balanced Hut it is impossible not to be struck with your 

 extent of knowledge in Geology, Hotany, and Zoology. 



Other thoughts were at the same time occupying his 

 mind. He had lectured that winter at the Royal Institu 

 tion, on &quot;The Relation of the Vital to the Physical Forces,&quot; 

 with especial reference to the life of plants, and had con 

 tested the doctrine of germ-force, maintaining that 



What the germ really supplies is not the force, but the direc 

 tive agency, thus rather resembling the control exercised by the 

 superintendent builder, who is charged with working out the 

 design of the architect, than the bodily force of the workmen, 

 who labour under his guidance in the construction of the fabric. 

 The agency of the germ may be regarded like Magnetism, as a 

 static force ; and just as Magnetism requires to be combined 

 with motion, to enable it to develop Electricity, so does the 

 directive agency of the germ need the co-operation of a dynamic 

 force for the manifestation of its organi/.ing power. That 

 dynamic force, as we learn from an extensive survey of the 

 phenomena of life, is Heat. 



The report of this lecture drew from the veteran 

 Mrs. Suinerville the following letter: 



Florence, June 12, 1860. 



The proof of the sequence of forces by which you have 

 connected mind with mind, and transmitted your ideas to the 

 minds of your audience, has required a higher power of intellect 

 than that of making electricity the bearer of thought from con- 



