188 On Ike Physiology of P'egelables. 



their exit as from a centre, and it serves as a strong part to ac- 

 celerate and fortify the powers before given to it by the muscular 

 force. I think, any one who will examine the strength of the bean 

 banner on the back of the red avtirrliivnm with care, can never 

 attribute such force to anv thing but a muscle pervading all ve- 

 ^etnble lije. The foldings of the last-mentioned flower are art- 

 ful and powerful, and the springs so admirably contrived as to 

 merit peculiar attention ; — most of the flowers of that kind have 

 tur> side-sprms;s to cowneci the two parts of the corolla together; 

 ti'.cy are unusuallv strong muscles. Trv their strength, and they 

 will he found powerful; thev lock one within the other: but when 

 the flower is dead, if the spring is examined, all the spiral will be 

 found dead and unwound, and broken in various places. 



I shall in a future letter give some beautiful specimens of the 

 mechanism Nature contrives in the opening and closing of the 

 flowers. The mechanic power is easily seen, so plain and sim- 

 ple as to explain itself. I shall also give a guess, " why Nature 

 does so at such different hours." It is a curious subject: but 

 a few general principles will be found to disseminate their powers 

 in a such a manner throughout all ves,etable life, as to be fully 

 competent to manage the whole ; and I hope by continuing my 

 dissections, and trusting to Nature onlv to prove her own work, 

 she will bring conviction of this important truth, and that I have 

 nothing to do in it, but obey and follow her. 



I am, sir. 



Your obliged servant, 

 D.iwlish, Sept. 1, 1816. AgNES IbBKTSON. 



Sketch of the Plate. 



Fig. 1. A specimen of the cylinders, which always enlarge at 

 top and spread when cut ; the flowers rising in them, and ar- 

 ranging themselves in a bouquet, when no longer pressed by the 

 vessels. 



Fig. 2. Dissection of the wood, cut perpendicularlv, showing 

 the buds AAA running to the bark. 



Fig. 3. The bud in the wood, showing it running through the 

 wood, with the juice surrounding it so as to guard it from being 

 touched by the hard part. 



Fig. 4. and 4*. Both showing the manner in which the bud 

 is thrown up into the new shoot, and the cause of every new 

 shoot being grooved. 



Fig. 5. Manner in which the vessels of the line of life in trees 

 arc often formed, marking a great contrast in those of the her- 

 baceous, which are in innumerable folds. 



Fig. 



