On the Buds and Ravil/icailr,?is of Pla/its. 321 



a revolution ov\ the circular head, whicli may be wrote 320-; 

 if, some little time after, by bringing the two images of tjic 

 same object in contact, I find the. number of revolutions and 

 parts to be 360, the difierence of the two obsiervations id -10, 

 therefore 40 : 320 ; : 1 : 8 (that is, .4,0, the xiifferea-je, 'is t(t 

 320, the first observation, as ] is. tog); consequently, we- 

 shall have gained in the chase oiie-ejghth part of ihc di- 

 stance : but if at the second obLiervation the number of re- 

 volutions be less, for instance 260, or two revolutions and 

 SO parts of a revolution; then, as 40, the. 4,iiierencc, isto 

 3S0, the first observation, €0 is 1 to 8 : consequently we 

 should have lost one-eighth part of our distance in the chase. 



Ko. 120, JMount-r.treet, 



Berkcley»square. .■..,, -r -, r 



XLVII. On the Buda and Rami/icafions af Pldntu', the 

 Birth of' these Qrgatfi, and the organic Relalinn bctiveen 

 the Trunk and the Branches: in a Latter fro)n G. L. 

 KoELEB, M, D. Professor of Botany and the Materia 

 Mcdica in the Provisional School of Medicine at Alentz, 

 to M. Ventenat, Member of the French National In- 

 ititute, 



■[ConcludecJ frcrm p. 2H.] 



JLjut it may be said, if these observations on the origin 

 of buds are founded in nature, how comes it to pass that 

 herbaceous and so tender bodies should penetrate through 

 a considerable number of ligneous- zones, which niust.be 

 the case in branches of two or three years of age, which, 

 though rarely, produce, however, sometimes biids ? It ap- 

 pears to me very probable, that at the period when the hud 

 beconjes expanded, a period which corresponds with the 

 elongation of the medullary sheath, a certain number of 

 the bundlas of the tubes of that sheath proceeds laterallv 

 from interval to. interval towards the bark. Soon after, the 

 first cambium of the bud appears between the medallary 

 sheath and the bark, and separates these two parts from 

 each other. This cambium does not long retain its muci- 

 laofinous form ; it is soon metamorphosed into the first liber 

 or hark. The bent vessels of this first liber, in hardenin<T 

 and becoming every day straighter, proceed towards thf: 

 nicdullary sheath, round which they compress them.selve?,, 

 and form there the first alburnum, which becomes then the 

 first ligneous zone. The prolongations of the medullary 

 ijhcaih are not all pinched by the formation of this first 

 X 3 stratum 



