A Considerable Accompt Touching Vegetable Excrescencies, Given by That Learned and Observing Gentleman, Mr. Martin Lister, in a Letter to the Publisher, of July 17. 1671. from York

A Considerable Accompt touching Vegetable Excrescencies, given by that Learned and Observing Gentleman, Mr. Martin Lister, in a Letter to the Publisher, of July 17, 1671, from York. I understand by yours of the 23th instant, that M. Ray cannot without much trouble retrieve the Letter, wherein I gave him formerly my opinion concerning Vegetable Excrescencies; and yet not wholly to deny you the satisfaction of what you seem much to desire, I am willing to think again upon the same subject, at least to recollect part of my former thoughts, as my memory will serve me. The occasion then of that Letter was upon the account given us by You in Numb. 57, of the opinion of the Italian F. Redi; Viz. that some live Plants or their Excrescencies do truly generate some Insects. To which opinion of F. Redi I told my friend, as I remember, that I indeed had observed, that the By-fruits of some Vegetables, as of the Oak and wild Rose, for example, did grow up together with their respective worms in them from small beginnings to fair and large fruit, some of them emulating even the genuine offspring of the plant, & miratur non sua poma. And further, that I did believe, the worms were furnished with food in and from them; but not by any Naval-connexion, as that Author fancies, and which I said, to me was unintelligible, and that I should be glad of a notion, which might make out to me such monstrous relation, as half animal half vegetable, or which is all one, Vegetable vessels inserted into an animal, or, the contrary. Strange Oeconomy! That it had never been my good fortune (whatever diligence I had used) to discern Eggs in the Center of Galls, but a worm constantly, even at the very first appearance, as near at least as my fortune led me. Yet I would not deny, but that diligence might one day discover the egg itself, which I was of opinion was affixed to or near the place by the parent-Insect, where the Gall rose. That I ever found the worms in all the excrescencies, that I had had yet met with, perfectly at liberty; and for the filaments, our Author mentions, it was very possible he might be mistaken, it being very hard, and a matter not yet treated of in any publick paper, which and what are the vessels that enter into the Texture of a Vegetable, as of a large Tree, for example; much more hard would it be to say, this is a vessel in a small Gall. That there were many By-fruits of different figure and shape (though perhaps of a like Texture) upon one and the same plant, every one of which did nourish and produce a different race of Insects: Whence, I told him, I thought might rather be argued the diverse workmanship of different Insects, than one and the same principle of vegetation to be Author of several sorts of Animals. That the Animals themselves, produced of such Excrencencies, were for the kind of such a race, as were well known to us to be otherwise generated of animal parents, and therefore it was probable, that these were so too, as well as their tribe-fellows. That the Insect-Animals produced of such Excrencencies were male and female; and that, if so, we might argue with Aristotle (lib. i. c. i. de Generat. Animal.) that Nature made not such in vain, and that, if from the coit of these Animals, which have their birth from no Animals, Animals should be born, they would either be like their parents and of the same species with them, and if so, it would necessarily follow (since in the generation of all other creatures it so comes to pass) that their very parents had such origin too: or unlike them, and if so (if these also were male and female) of this second unlike offspring a third race of different animals or species would be begot, and of them a fourth, and so in infinitum. And that these Insects, which he and I had observed to be produced of the Excrencencies of some vegetables, we had good cause to suspect they were male and female, since some of them had stings and were tripulous, and others not (vide Catalog. plant. Cantab. ad Rosam caninam & alibi.) These were some at least of the Arguments, as far as I remember, I used, when I formerly wrote on this subject to my friend; but since that Letter, I have perused the Book of F. Redi itself, and do find, that the said opinion is barely propoted as a thing not unpleasible, but the proofs thereof are reserved, till the publishing of a curious piece, concerning the *Excrescencies* of the Oak; and therefore I shall be less earnest in the refutation of that opinion, which perhaps a more accurate search into Nature will in time make the Author of it himself find erroneous. I presume not to venture to decide this controversy, my experience in these matters being too insufficient, and my leisure and health but little to hasten a convenient stock of particulars, and a due examination of them; yet before I leave this subject, I am willing to run over and present you with a few abbreviated instances of some of the several kinds of Vegetable Excrescencies, and likewise some un-obvious ways of Insects feeding on plants; and these I shall deliver in confirmation of the following Propositions. 1. That all are not truly Vegetable Excrescencies that are reputed such. And here we may justly name the *Purple-Kermes*, for example, whose history you were pleased to publish in *Numb.* 73. This, I say, both gives a clear light to the discovery of the nature of the *Scarlet-Kermes*, (a thing wholly unknown to the Ancients, as far as we can see by their writings, and no less ignored by the moderns, and yet, which is admirable, in very great esteem and continued in use for some thousands of years,) and also is an evident instance, that some things, confidently believed Vegetable Excrescencies, are no such matter, but Artificial things merely contiguous to the plant, and which have no other relation to it than the *patella*-shellfish to the Rock it cleaves. 2. Generally, Insect Eggs laid upon the leaves of plants, or their respective worms feeding on them do not occasion or raise Excrescencies. This truth every body, that hath been the least curious, is an Eye-witness of. Thus, for example, the Eggs of the common *Red butterfly*, laid upon the Nettle, are thereon hatched without blistering the plant into an Excrecence, and the stiff haired or prickly *Caterpillars* hatched from them Eggs, feed upon the leaves without any ill impression, puncture, or prejudice, save that they make clean work, and eat all before them. I could produce some hundreds of instances, if this were to be doubted of. 3. Some Insect-eggs, laid upon the leaves or other parts of plants, do, as soon as hatched, pierce and enter within the plant plant to feed. To give you a convincing instance to the truth of this proposition, take this from my notes. May 22, I observed on the back or underside of the leaves of *Atriplex olida*, certain small milk-white oblong Eggs, on some leaves four, on others fewer, or more; these Eggs were on some plants yet unhatched, but on many of the same plants I found the Egg-shells or skins yet adhering to the leaves, and the little maggots already entered (through I know not what invisible holes) within the two membranes of the leaf, and feeding on the inward pulp or substance of the leaf: in other leaves of that plant, (he that shall make the observation after me, will find plants enough of this species feized on, to vary, as I did, the observation in one day,) I found those maggots grown very great, and yet the two membranes, that is, the uppermost and undermost skin of the leaf, entire, but raised and hollow like a blather. Note 1. That those maggots were of a Conick shape. 2. That in July they shrunk into Fly Chrysalis's, and accordingly came to perfection, &c. To this unobvious way of feeding we think we may refer all worm-eaten fruits, woods, &c. 4. Worms feeding within some of the parts of some plants do cause Excrencencies. Thus the heads or feed-vessels of *Papaver*, *Spart.*, *Sylv.*, *Ger.*, *Emac.*, &c. are disfigured for having worms in them, and grow thrice as big, as the not seafed ones. This is also plain in the Excresc. of *Pseudo teucrium*, and *Barbarea*, &c. 5. The substance of most Vegetable Excrencencies is not the food of the worms to be found in them. The instances given in confirmation of the last proposition do also confirm this: neither is an Oak-apple properly worm-eaten, or the shagged Galls, or Sponges of the Wild Rose, or the Smooth ones on the leaves of the same plant, or the Baggs upon the leaves of the yellow dwarf Willow or the Elm, &c. This is the sum of what I have to say at present concerning this subject, being very unwilling to advance further, than my own private observations will suffer me.