THE POISONOUS PLANTS OF BOMBAY. 357 



developed they are very opaque, and their whole structure remarkably 

 tough. The stalk penetrates a considerable distance into the fully- 

 formed head, so as to make the base of the gland dome-shaped 

 or conical. Younger and smaller external glands are fairly 

 translucent. The stalks of almost sessile glands are composed of a few 

 comparatively large cells." Sessile glands are also to be seen in 

 Plumbago rosea on the inner face of the sepals. Their basal cells are 

 two. " Their homology with the stalked glands on the exterior of 

 the calyx," says Dr. Wilson, " traced through the smaller and almost 

 sessile ones there, cannot be doubted. Further, the sessile glands do 

 not offer any point of material distinction from normal mucilage- 

 glands of the leaves." 



POISONOUS PROPERTIES. 



The plant which Rumphius has described so graphically and fully 

 under the name of Radix vesicatorius* (the blistering root), is un- 

 mistakably the Plumbago rosea of Linnaeus. That this name has not 

 been given without reason will be apparent from the following 

 observations. It is the root of the plant which is the most obnoxious 

 of its entire organization. Its juice is very acridly pungent to taste, 

 and produces in the tongue a severe lancinating pain. To do this it 

 must be fresh. The juice distinctly blisters the skin and otherwise 

 irritates it as violently and briskly as cantharides. "Within six to 

 eight hours, says Rumphius, the skin becomes red and covered with 

 blebs. Rheedef observes that the leaves and stems are also pungent 

 to taste, but are not so virulent as the root. More than one writer has 

 said that the virulent effects are more marked when the juice is taken 

 from a fresh root. Why is it so ? Is it that the irritant property is 

 due to an evanescent active principle, an essential oil or ether which 

 deteriorates in course of time as the root dries up ? Seventy years ago 

 M. Dulong isolated an acrid active principle called Plumbagin from 

 Plumbago europcea, the only European congener of Plumbago rosea. 

 From the researches of O'Shaughnessy it appears that the same 

 active principle is found in Plumbago rosea. It abounds chiefly in 

 the bark of the root. "It occurs in brilliant yellow crystals, of 



* Herb. Amb., Lib. is, cap. 68, p. 453. 

 f Hortus Malabaricus, vol. s, t. 9, p. 17. 



