62 



ORGANOGRAPHY. 



instead of bcinj? thus touched lightly, be grasped firmly, the 

 sting becomes broken, and as the sharp point does not then enter 

 the skin, no irritation is produced. 



Fig. 129, 

 Fig. 128. 



Fig. 128. Sting of a species of INfalpighia. 

 c. Epidermis, h, h, g. Glandular appa- 

 ratus Fig. 129. Sting of the conimon 



Kettle ( tXi'ca f/(0(c«), consisting of a 

 single cell with a bulbous expansion at 

 its ijase, b, and terminated above by a 

 swelling, s, and containing a granular 

 irritating fluid, /. w t. Epidermal ceils 

 surrounding its base. 



b Internal Glands. — These are spaces containing secretions, 

 situated below the epidermis, and surrounded by a compact 

 layer of cells {figs. 130 and 131). They are closely allied in 

 their nature to receptacles of secretion (see p. 54) ; in fact, 

 in many cases, can hardly be distinguished from them, hence 

 it would be probably better altogether to refer them to those 

 organs. In some cases they are of small size, as in the leaves 



Fig. 130. 



Fig. 131. 



Fig. If'.O. Gland from the leaf of the common Rue {Hiila graveolens). 

 g. Gland surrounding a cavity, I, and itself surrounded by the epi- 



dcrmiii. c, and the ordinary cells of tlie leaf, wc. Fig. 131. Internal 



glands or cy«te from the rind of an orange. 



of the 1\nc (fig. 130), Dittany, Myrtle, Orange, Lemon, St. 

 John's Wort, &c. In such K-avos they may be readily obscn-ed 

 by holding them up against the light, when they ajjpcar as 



