346 MISCELLANEOUS. [l88l. 



Galls. 



[Shortly before his death, my father began to experimentise 

 on the possibility of producing galls artificially. A letter to 

 Sir J. D. Hooker (Nov. 3, 1880) shows the interest which he 

 felt in the question : — 



" I was delighted with Paget's Essay ; * I hear that he has 

 occasionally attended to this subject from his youth .... 

 I am very glad he has 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. 

 He imagined to himself wonderful galls caused to appear on 

 the ovaries of plants, and by these means he thought it possible 

 that the seed might be influenced, and thus new varieties 

 arise. He made a considerable number of experiments by 

 injecting various reagents into the tissues of leaves, and with 

 some slight indications of success.] 



Aggregation. 



[The following letter gives an idea of the subject of the 

 last of his published papers.f The appearances which he 

 observed in leaves and roots attracted him, on account of 

 their relation to the phenomena of aggregation which had so 

 deeply interested him when he was at work on Drosera :] 



C. Darwin to S. H. Vines. % 



Down, November 1, 1881. 

 My DEAR Mr. Vines, — As I know how busy you are, it 

 is a great shame to trouble you. But you are so rich in 



* 'Disease in Plants,' by Sir ciety.' Vol. xix., 1882, pp. 239 



James Paget. — See Gardeners' and 262. 



Chronicle, 1880. % Reader in Botany in the Uni- 



f ' Journal of the Linnean So- versity of Cambridge. 



