Darwin Correspondence Project

I feel considerable difficulty in expressing an opinion on this paper, from not knowing how few Botanists have generally supposed that the sacs &c are independent growths in the plants. If this be so, as I suppose from the terms used, it seems to me highly desirable that the facts, here recorded and observed by a naturalist on the spot, should be published; more especially as Mr Spruce shews under what conditions and contingencies the sacs are formed. The presence of sacs &c in plants belonging to various widely different orders, is also a very interesting circumstance. But the point which Mr Spruce seems to think the most important, namely that the sacs in the course of ages have become inherited, is manifestly very improbable, and appears to rest on hardly any evidence. The evidence advanced is, firstly, the generality of the presence of sacs, accompanied however by an almost equal generality in the presence of ants, in certain species; and secondly, that he saw in one case (p. 6) sacs beginning to be formed long before any ants had visited the plant. But it seems to me not a little doubtful that it could have been positively ascertained that ants had never visited such plants; and Dr Hooker informs me that none of the Melastomas have ever produced sacs in the hothouses at Kew. I would suggest that the paper should be printed, with two or three illustrations, on condition that the author is willing to alter the title and to strike out several short passages (marked with pencil) in which the sacs &c. are spoken of as being inherited. The author might of course state that he had been led to suspect that these structures are now inherited, and this might lead to further investigations; but to speak positively on the subject of inheritance without much fuller evidence would be in my opinion injurious to the reputation of the author and of the Society.

To the President | & Council of the | Linnean Socy.