114 GEOEGE JOHN EOMANES 1881 



making a hole into the summit of the ovarium and 

 then inserting pollen caused the fertilisation of the 

 ovules. This has always stretched my belief to the 

 cracking point. I think he has published a notice 

 on this experiment, but forget where, and I think it 

 was on ' Papaver.' Dyer could probably tell you 

 about it. Perhaps your plan is to remove one half of 

 the ovarium of a one-seeded plant and join it on to 

 the ovary of another of a distinct var., with its ovule 

 removed; but this would be a frightfully difficult 

 operation. 



I am very sorry to hear about your ill success 

 with cats, and I wish you could get some detailed 

 account of the Belgium trials. 



Yours very sincerely, 



C. Darwin. 



April 16, 1881. 



My manuscript on Worms has been sent to 

 printers, so I am going to amuse myself by scribbling 

 to you on a few points ; but you must not waste 

 your time in answering at any length this scribble. 

 Firstly, your letter on intelligence was very useful 

 to me, and I tore up and rewrote what I sent you. 

 I have not attempted to define intelligence, but have 

 quoted your remarks on experience, and have shown 

 how far they apply to worms. It seems to me, that 

 they must be said to work with some intelligence, 

 anyhow, they are not guided by a blind instinct. 



Secondly, I was greatly interested by the abstract 

 in ' Nature ' of your work on Echinoderms ; the com- 

 plexity, with simplicity, and with such curious co- 



