i868-i88i] GALLS W5 



remarks on Herbert Spencer. 1 . . . Our recent visit to < am- Lettei 

 bridge was a brilliant success to us all, and will ever be 

 remembered by me with much pleasure. 



T( i James Pag I Letter 757 



During the closing years of his life, Darwin began to experimentise 

 on the possibility of producing galls artificially. A letter to Sir J. D. 

 Hooker (Nov. y.\. 1S80) shows the interest which he felt in the 

 question : — 



" 1 was delighted with Paget's essay 5 ; I hear that he has occasionally 

 attended to this subject from his youth. ... I am very glad he h 

 called attention to galls : this has always seemed to me a profoundly 

 interesting subject ; and if I had been younger would take it up." 



His interest in this subject was connected with his ever-present wish 

 to learn something of the causes of variation, lie imagined to himsclt 

 wonderful galls caused to appear on the ovaries of plants, and by tin 

 means he thought it possible that the seed might be influenced, and thus 

 new varieties arise. 3 lie made a considerable number of experiments by 

 injecting various reagents into the tissues of leaves, and with some slight 

 indications of success. 4 



The following letter to the late Sir James Paget refers to the same 

 subject. 



Down, Nov. 14th, 1 



I am very much obliged for your essay, which has inter- 

 ested me greatly. What indomitable activity you have ! It 

 is a surprising thought that the diseases of plants should 

 illustrate human pathology. I have the German Encyclopedia, 

 and a few weeks ago told my son Francis that the article on 



1 Prof. Balfour discussed Mr. Herbert Spencer's views on the genesis 

 of the nervous system, and expressed the opinion that his hypothesis 

 was not borne out by recent discoveries. "The discover)- that ner\> 

 have been developed from processes of epithelial cells gives a very 

 different conception of their genesis to that of Herbert Spencer, which 

 makes them originate from the passage of nervous impulses through a 

 track of mingled colloids. . . . ; ' (/or. cit. y p. 644.) 



5 An address on "Elemental Pathology," delivered before the British 

 Medical Association, August 1S80, and published in the Journal of the 

 Association. 



3 There would have been great difficulties about this line of research, 

 for when the sexual organs of plants are deformed by parasites in the 

 way he hoped to effect by poisons) sterility almost always results. See 

 Molliard's "Les C6 idies Florales," Ann. Set. Nat., 1895, Vol. I., p. 1 



4 The above passage is reprinted, with alterations, from Life tint/ 

 Letters, III., p. 346. 



