[29] Diagram for a lecture on 'Mental Evolution.'
[30] See Nature, vol. xxi. p. 207.
[31] Mr. Romanes used to describe with much amusement the ludicrous nature of the experiment as seen by passers-by. He drove in a cab well into the country, released the cats, and mounted the roof of the cab in order to get a good view of the cats speeding away in different directions.
[32] A letter written at the end of April 1881.
[33] International Medical Congress.
[34] See 'Life &c. of C. Darwin,' vol. iii. p. 210.
[35] Charles Darwin: a memorial poem.
[36] A few stray poems in magazines.