270 M. Lestiboudois on the Vessels of the Latex, 



bark and in certain cortical layers interposed between the lig- 

 neous tissue of one of the Convolvuli from Brazil. The same 

 thing may be seen in the Convolvulus nervosus. 



In the root of Convolvulus Turpethum the proper juices are 

 very abundant, and concrete into a yellow resinous substance 

 enclosed in utricles, often considerably elongated. 



This modification of form of the reservoirs of the coloured 

 juices is not encountered only in the roots of plants, but also 

 elsewhere. Thus, both in the external and intermediate cortical 

 laminse of the stem of Glycine, red points are seen scattered 

 here and there on the outside of the cortical fibres, formed of 

 cells (utricles) varying in length, more or less regular, and 

 having their internal wall lined with a substance which appears 

 yellow under the microscope. These utricles are disposed in 

 such a fashion as to constitute fibres or bundles, which cannot 

 be regarded otherwise than as analogues of vasa propria, although 

 no exudation of coloured fluid ensues when sections of this plant 

 are made. Certain species of Sapindacese also present series of 

 coloured utricles, which, on a section of the stem, look like co- 

 loured specks, and whose organization is analogous to those of 

 Glycine. 



It follows, therefore, that the appellation " vessels " cannot be 

 always given to those organs that contain coloured juices, and 

 that the more general term reservoirs is better adapted to them. 



This conclusion is so much the more necessary, inasmuch as, 

 in certain instances, the utricles are not even disposed in linear 

 series. For example, in Piper Siriboa the parenchyma of the 

 external bark, as well as that of the intermediate cortical layers 

 and the pith, has numerous reddish spots scattered throughout 

 it, composed of cells having walls discernible with difficulty 

 on account of their being overspread with a coloured material 

 that is unequally difi'used and analogous to that which lines 

 the cells of Glycine and Sapindacese ; but these utricles, instead 

 of being placed in rows, and thereby approaching the characters 

 of vessels, are accumulated in irregular masses of a more or less 

 rounded outline. 



Further, the elaborated juices of plants are met with not only 

 enclosed within vessels and utricles, but also difi'used in inter- 

 cellular passages, or the natural interspaces between the cells, 

 found especially at their angles of junction. They are likewise 

 met with in regular lacuuee, formed by the separation of adjoin- 

 ing cells, and also in irregular lacunae resulting from lacerations 

 of the tissues. When they occupy intercellular spaces, they do 

 not attain the same dimensions as the cells, inasmuch as they 

 are contained in the intervals left between those portions only 

 of the cell-walls which are not adherent throughout their whole 



