Retrospective Criticism. 433 



each joint or limb has an individual circulation ; and although it may have 

 a communication with other joints, yet that its motion is complete in 

 itself. The section of a rootlet, or of a joint, shows it to consist of 

 (the plant consists chiefly of tubes, which are somewhat tou^h and 

 flexible : when any of these are cut, that length is killed, and nearly all 

 the contents run out, therefore its true section cannot be seen ; but, from 

 careful and repeated examinations, Mr. Varley has ascertained that, sup- 

 posing the section could be obtained, it would consist of) two lateral 

 simple semilunar ducts (Jig. 82.: this fact Mr. Varley discovered, and 

 told to Mr. Burnett, who ought not to have used it without 

 acknowledging whence it came), each being the channel of a 

 current that traverses the joint in an opposite direction to the 

 other; the course of the one being up, the other down." And 

 from the great similarity exhibited by all parts of the Chara 

 we may safely infer that such a section will serve for each 

 portion even of the root ; for although they are no thicker 

 than the finest cobweb, yet, when highly magnified, they exhibit the same 



kind of circulation. 

 The extremely thin in- 

 ner cellular membrane 

 which divides the sap 

 from the central fluid, 

 is attached to the tubes their whole length at two opposite sides, which 

 lines of attachment take a spiral course around the tubes. (Jig. 83.) 



Now, Sir, 1 send the following statement, that you may know the 

 facts. Because Mr. Burnett found it difficult to manage the Chara, he 

 requested me to favour him by exhibiting it for him, at his opening lecture 

 at the King's College, and I have since supplied him with an apparatus of 

 my contrivance, by which it may be kept growing, and ready for instant 

 inspection during many weeks (which machine he has never recharged 

 with Chara himself, but always sent to me to be replenished) ; and it has 

 so happened, that nearly all the Chara that has been publicly exhibited 

 during the winter, was of my providing and fitting for microscopic use. I 

 have repeatedly exhibited it at the Royal Institution at their Friday even- 

 ing meetings ; and at the Tuesday evening meetings of the Society of Arts, 

 &c. ; and have in the 48th vol. of the Transactions of the last-mentioned 

 Society, given a tolerably full description, accompanied by engravings, of 

 the plant. I believe, if Mr. Burnett had attempted to dissect the Chara, 

 he would never have said that " a section of a rootlet, or of a joint (see 

 p. 143.) shows it to consist of lateral ducts," &c. ; for it shows no such 

 thing : nothing is seen but a tube, somewhat like a quill, dirtied by some 

 of the broken up membrane that had been on it. I have washed short 

 lengths of this membrane out in two ribands, and also as a whole tube. 

 It consists of minute cells united by a membrane so extremely thin as not 

 to be touched without damage. Leaving these facts entirely at your dis- 

 posal, 1 have only to add that I shall be happy to show you nay con- 

 trivance for preserving such objects alive, and quite ready for placing under 

 the highest power of a microscope. I remain, Sir, yours, &c. — Cornelius 

 Varley. Charles Street, Clarendon Square, Somers Town, June, 1832. 



Corrections for this Magazine, and for the Encyclopaedia of Gardening. — 

 Sir, As you appeared to consider my contributions to your Magazine to 

 be of little importance, and to treat me with indifference, I withdrew my 

 attention from it altogether from June, 1830, and should not have troubled 

 myself further about it, had not a young nurseryman, on inspecting my 

 trees, observed that he had seen my method of training my reversed 

 dwarfs, published in your Magazine, Vol. VIII. p. 437., which he took in. I 

 borrowed it of him, and also your Encyclopaedia of Gardening, which I 

 had not before seen ; and, notwithstanding you published mv paper of 



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