I am working hard at the jelly-fish just now, and have succeeded in extracting several new confessions. The nerve-plexus theory, in particular, is coming out with greater clearness. The new poisons, too, are giving very interesting results. I suppose you do not happen to know where I could get any snake poison. The 'Phil. Trans.' seem very long in coming out. I have not yet got the proofs of my paper. June 6, 1877. I am very glad you sent me the extract from Lamarck, for I had just been to the R.S., hunting up several of the older authors to see whether any mention had been made of the theory before Spencer wrote. While at Down I forgot my speculations about inter-crossing, and, therefore, although I do not think they are much worth, I send you a copy of my notes. The ideas are not clearly put--having been jotted down a few years ago merely to preserve them--but no doubt you will be able to understand them. Do not trouble to return the MS. I had intended to ask you while at Down if you happen to know whether stinging nettles are endemic plants in South America. The reason I should like to know is, that last year it occurred to me that the stinging property probably has reference to some widely distributed class of animals, and being told--rightly or wrongly, I do not know--that ruminants do not object to them, I tried whether my tame rabbits would eat freshly plucked nettles. I found they would not do so even when very hungry, but in the same out-house with the rabbits there were confined a number of guinea-pigs, and these always set upon the nettles with great avidity. Their noses were tremendously stung, however, so that between every few nibbles they had to stop and scratch vigorously. After this process had been gone through several times, the guinea-pig would generally become furious, and thinking apparently that its pain must have had some more obvious cause than the nettles, would fall upon its nearest neighbour at the feast, when a guinea-pig fight would ensue. I have seldom seen a more amusing spectacle than twenty or thirty of these animals closely packed round a bunch of nettles, a third part or so eating with apparent relish, another third scratching their noses, and the remaining third fighting with one another. But what I want to ask you is this. Does it not seem that the marked difference in the behaviour of the rabbits and the guinea-pigs points to inherited experience on the part of the former which is absent in the case of the latter? If nettles are not endemic in South America, this inference would seem almost irresistible. Dr. Hooker tells me nettles grow there now, but he does not know whether they did so before America was visited by Europeans. Possibly there might be some way of ascertaining.