120 Retrospective Criticism. 



As to the third charge, which says " that no man was more given to 

 sneers of this kind than Linnaeus," I need not say much, as I do not know 

 that any instance can be proved, except it be Bufonia, in framing which 

 name he is said to have mahciously omitted an f : and who will deny 

 that BufFon was in many things "a toad-eater ?" For this single peccadillo, 

 shall it be said that no man was more given to such faults ? It is surely too 

 sweeping an expression. — Q. E. I). Limerick, November, 1830. 



The author does not seem to be aware that Mr. Salisbury declared, 

 after he had quarrelled with Sir James Smith, that he had recorded 

 in the Smithia sensitiva the peculiar irritability of the President of the 

 Linnean Society. The passage as to Vaillant was introduced by Mr. Lind- 

 ley, to whom we shall be happy to afford space to vindicate himself, should 

 he think it necessary so to do. — Cund. 



Mr. TTiomp&orC s Physiological Experiments. — Sir, In your valuable Ma- 

 gazine (Vol. V, p. 253 — 257.) are some physiological botanical experiments 

 on vines. It is a laudable amusement ; yet I think Mr. Thompson sets out 

 under a mistaken notion of the motion of the sap (p. 253.). He says, the 

 top buds vegetated the thirteenth day, and, by wounding the bark, he dis- 

 covered the descent of the sap ; but the vines sickened, and the roots pro- 

 duced new shoots. Now, Sir, it is my opinion the sap in the vine was 

 forced into motion, whilst the root was dormant in the cold prison of a pot. 

 It is my opinion, also, that the cause of the failure was owing to the want 

 of heat at the root. 



He found (p. 254.) the sap descend regularly, until it got to the front 

 wall, but it took four days more time to descend than it did over the same 

 length in the warmer climate ; and it bled freely at the surface of the soil. 

 Is not this proving a non-circulation of the sap in trees ? as it appears 

 by the watery effusion, or bleeding at the root, whilst the head was dry. 

 Allow me to ask, whether this bleeding was from the roots or branches : if 

 it did not come from the roots, how or whence came the second vegetation ? 

 (p. 255.) These remarks are valuable proofs that the sap in the tops of 

 trees can be excited independently of the roots or stem. At the same 

 time, the birch and vine (p. 256.) prove a non-circulation of sap, by the 

 former experiments, and the free quick vegetation of the latter when the 

 sap was excited in roots and branches at the same time. 



In p. 257, he again adverts to his mistaken idea of the sap resting in the 

 young wood ; not reflecting that the sap in the delicate young shoots is not 

 only nearest to the sun, but Ae sap in them is put in motion by less 

 heat. He notices a mucilaginous matter (p. 256.), but without making any 

 comment. I am. Sir, &c. — J. S. May, 1830. 



Further Remarks. This is the most interesting subject in nature. Mr. 

 Thompson quotes Mller's Dictionary on peach trees being planted too 

 deep; for, the sap in the branches being put into motion in spring, its 

 strength is exhausted before the sun can affect the roots to put the sap of 

 them into motion, which causes the bloom to fall and the shoots to languish. 

 This is precisely the case with his vines, (p. 254.) Does not this prove that 

 frequently digging fruit-tree borders destroys all the roots that are near the 

 surface, which paralyses deep planting ? He says Mitchell's Dendrologia 

 denies any cli'culation of sap. On your recommendation I pm'chased that 

 work, and by it I am his proselyte. I wish he had commented u^^on it ; I 

 should like his opinion. In p. 258. he has drawn freely upon the Den- 

 drologia, p. 143. 147. 157. and 162. It goes deeper into vegetative motion 

 of sap than any other work I ever saw. In Vol. V. p. 421., the American 

 Arborator, like Mr. Evelyn, has fallen into a mistake about the succession 

 of trees to compose new natural woods of beech after oak. I fiud this phe- 

 nomenon accounted for by Mitchell, p, 73. I hope this will be a stimu- 

 lus to such laudable exertions as those of Mr. Thompson, and to the 



