



■ppear in the form of a fine downiness. An examination of the anatomical itnicture of this part 



has revealed some facts which deserve to l*e described. 



Let the direction* m the bottom of ih« plita represent very thin vertical dice* of tin* thick 

 base of the lip, magnified about 500 lime* in diameter. A shew* tlio appearance of the* tubercular 

 lining, three of the glittering callosities being cut through ; they consist of cellular time arranged 

 with great regularity* and there is no distinct cuticle, but UiO thickness of the sides of the exterior 

 cells is greater than that of the interior : some of the cells are filled with yellow colouring matter 

 or chlorophyll of a granular nature, others contain a rod fluid (l t 1); the yellow in the cells next 

 the surface (2,2) is paler and less granular lb;m that in the inner cells (3, 3) ; cell* still further 

 from the surface (4) gradually contain less granular matter, which appears to slick exclusively 10 



the side*, and not to float iu the interior. B represent* a similar view of the tissue forming the 



outer surface, at a part where the colour i* uniformly yellow; the whole of the colls contain 

 exclusively yellow granular matter, which becomes less dense as you proceed from the surface (4) 

 towards the interior (ft) ; here also there is no distinct cuticle, or layer of empty cells ; the surface 



is covered closely with conical cells, which form the almost invisible downiness of that port C is 



a similar view of the same part, at u place where the colour is both yellow and purple ; it is more 

 magnified ; in this case it is seen that the colouring matter is distinctly separated into Separate cells, 

 and that the colour of one does not interfere with that of the other, but that the yellow is lodged 

 m one cell (1,5) and the purple in others (4); the hairs themselves are sometimes filled with purple 

 fluid, as at 3 ; sometime-** they arc almost colourless, as at 4 ; or they are stained yellow, by the 

 addition of grumou* matter of that colour to their interior, as at I. At 3. it is seen that the hairs 

 occasionally grow together at the base* 



Thus it appears that the varying lini* of colour which are found in flowers are not produced by 

 colours proper to tho tissue of which they are composed, or by n confuted mixture of colouring 

 matter below the surface, hut arc caused by different colours, separately deposited in separate cells, 

 which are themselves uniformly colourless ; I could not perceive that any of the yellow was ever 

 developed in the purple cells, and certainly the reverse did not exist ; now and then yellow colour 

 appeared to come from the interior of a purple cell, but this I believe was owing to a purple cell 

 being placed between the eye and a yellow cell. These facts are in accordance with what has 

 been observed by Botanists in other case*. 



The yellow cells uniformly presented a grutnoiis or granular appearance, in consequence of 

 their chlorophyll being collected into irregular spherules of various sixes, but I could not succeed 

 in delecting any amylaceous mutter iu the interior of the spherules. The effect of applying tincture 

 of iodine was to destroy the brilliant orange yellow, and to convert it into that dull olive brown which 

 usually follows the application of this agent to the resinous secretions of plant*, but I sought in vain 

 for any *ign of blue in the interior of the granules* In one case* however. I remarked a small portion 

 of the membrane of a cell stained blue, much in the same way us is represented in Link's Iconts 

 Anatomic**, tab. xvi. fig. 13 in the tubercle of Salop. The application of dilute sulphuric acid 

 coagulated the yellow granules into a ball in the middle of each cell, and changed their colour to an 



olive green. 



While the yellow colour appeared to Ire entirely produced by tho presence of matter in a 

 granular state floating in colourless fluid, the purple was iu many cells as uniformly caused by 

 n purple fluid without granule : but in the deepest coloured cells, as at C 2, and 3, there was 

 evidently a tendency to granulation, although, when the contents were pressed out of such cells, no 

 distinct granules could be found. Iodine produces uo other effect Upon the purple than to render 

 its colour less brilliant ; but diluted sulphuric acid, without discharging the colour, renders it distinctly 

 grnmOUi, I do not know whether lUia effect is produced by the acid coagulating the purple 

 chlorophyll, or whether it merely renders distinct and firm that which was previously semifluid and 

 undUiin<ruUhnhlo. I am however persuaded that the amylaceous centres, round which Professor 

 Mold conceives the chlorophyll to mould itself in the interior of vegetable tisane, do not exist in 

 this Instance- 



