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On the Hombothermal method of Acclimating [April 



V. — Further Observations regarding the Hombothermal method of 

 Acclimating Extra-Tropical Plants within the Tropics, — By 

 Robert Wight, Esq. m. d. &c. &tc. 



It will be recollected that the Homoothermal method of acclimating, 

 rests on the supposition, that plants raised from seeds, sprouted under a 

 high temperature, have their constitutions so modified as to fit them for 

 successful culture in higher temperatures,* than if raised in the usual 

 manner under shade. In the following remarks, I shall offer some 

 further elucidations of the method, and propose some experiments, 

 which will go far, I think, either to refute the argument, or to establish 

 the plan on a firm foundation. 



I have recently met with two papers bearing indirectly on the sub- 

 ject; to give some account of which and show their application to 

 practice, are my reasons for now resuming its consideration. The first 

 of these is a letter from N. B. Ward, Esq. of London, to Dr. Hooker, 

 published in theCompanion to the BolanicalM agazine, vol. 1st, page 317, 

 — " On an improved method of transporting living plants ;"f the other 

 a memoir, by Messrs. Milne, Edwards and Colin — " Sur la vegetation des 

 Cereales sous de hautes temperatures." Mr. Ward informs us that the 

 simple incident of burying the chrysalis of a sphynx in some moist 

 mould, contained in a wide-mouthed glass bottle, lightly covered, led 

 him to the discovery, that earth so situated was always equally moist 



* Since this paper' was sent to the press, I have met with the following very apposite 

 fact in support of the principle, and strongly corroborative of the method of acclimating, 

 advocated in my former paper.— " I remarked that in coffee-plantations the nurseries 

 are formed not so much by collecting together those young plants which accidentally rise 

 under the trees that have yielded a crop, as by exposing the seeds to germination during 

 fine days in heaps between plantain leaves. These seeds are taken out of the pulp, but 

 yet retaining part of it adhering to them. When this seed has germinated, it is sown, and 

 produces plants that can bear the ardour of the sun better than those that spring up in 

 the shade in the coffee-plantations." — Humboldt's Personal Aarative, Eng. Edit. 4, 

 pages 67, 68. 



The heat developed by the fermentation of the adherent pulp, seems in this case to 

 cause the rapid germination here mentioned, and to produce the constitutional change 

 on the plants which enables them to " resist the ardour of the sun better than those that 

 spring up in the shade." More conclusive evidence uf the truth of the principle ex- 

 plained could scarcely, in my opinion, be adduced. 



+ Republished among the "Selections," at the end of this Number. The British As- 

 sociation for the Advancement of Science has considered this subject of importance 

 sufficient to induce them to offer a premium for experimental researches regarding it.— 



Editor. 



