18SI FLASHING LIGHT ON PLANT TISSUES 103 



had utterly forgotten how good it appears when dressed 

 up in your article. Yours very sincerely, 



Chaeles Dabwin. 



I have had a hunt and found m}' little article on 

 Geese, which please hereafter return. 



From G. J. Bomanes to C. Daricin, Esq. 



IS Cornwall Terrace, Eegent's Park, X.W. : December 10, 1880. 



I return hy this post the book on Hybridism, 

 ■\nth manj^ thanks. It has been of great use to me 

 in giving an abstract of the history. 



I have read your own book mth an amount of 

 pleasure that I cannot express. 



One idea occurred to me with reference to lumi- 

 nous stimulation, which, if it has not already occurred 

 to j"ou, would be well worth trying. The suggestion 

 suggests itself. How about the period of latent stimu- 

 lation in these non-nervous and jet irritable tissues ? 

 And especially with reference to luminous stimulation 

 it would be most interesting to ascertain whether the 

 tissues are affected by brief flashes of hght. If you 

 had an apparatus to give bright electrical sparks in a 

 dark room, and were to expose one of your plants to 

 flashes of timed intervals between each other, you 

 might ascertain, first, whether any number of sparks 

 in any length of time would affect the plants at all ; 

 and second, if so, what number in a given time. I 

 should not wonder (from some of my experiments on 

 Medusae, see ' Phil. Trans." vol. clxvii. pt. ii. pp. 683-4) 

 if it would turn out that a continuous uninterrupted 

 series of sparks, however bright, would produce no 



