the Vasa propria, and Receptacles of the Juices of Plants. 345 



granuliferous liquid is reduced to the appearance of a feeble 

 streak of little corpuscles ranged in a single line. Some of these 

 tubes present oblique or transverse articulations derived from 

 the union of the tubes with those which are continuous with 

 them. These tubes, by reason of their transparency, of the 

 tenuity of their walls, of the absence of fissures (clefts) and 

 perforations, and of the presence of granules floating in their 

 contained fluid, resemble in some respects the vessels filled with 

 coloured liquids ; but, on the other hand, they present differences 

 of a very decided nature. The tubes filled with milky juices 

 are flexuose, branching, and anastomotic, whereas these others 

 are straight, parallel, placed in close juxtaposition, and closed at 

 their extremities, as in the plants already enumerated, and in 

 many others we have examined — as, for instance. Arum Italicuin, 

 Impatiens balsamina, Menyanthes trifoliata, Cijnara Scolymus. 

 &c. We have observed in certain plants (for instance, in Bras- 

 sica oleracea) the commencement of divisions of the tubes, but 

 no anastomoses, and no indications of a complex network. 



How does it happen that so skilful an observer as M. Schultz 

 has assumed the existence of, and figured, this reticulated arrange- 

 ment ? Is it owing to the influence of the hypothetical system 

 he adopted ? Is it on account of the partial divisions he may 

 have noticed ? Is it because that in certain cases, where the 

 cells have been partially destroyed by maceration, they still 

 offer resistance to separation along their lines of junction, and 

 exhibit a sort of network, as we have seen them do in several 

 instances ? Or is it, lastly, on account of mycodermic filaments 

 developed in the macerating fluid, and presenting themselves in 

 the form of transparent, ramifying, and sometimes articulating 

 tubes, having been mistaken for structures belonging to the 

 plant on which they were produced ? We cannot reply to these 

 queries ; but in the many observations we have made and often 

 repeated, we have failed to encounter these reticulated tubes, 

 which have been represented as the analogues of proper vessels. 



With reference to the three states of articulation, expansion, 

 and contraction admitted by M. Schultz, these appear to me 

 to be the consequences either of the natural structure of the 

 tubes, or of the modes of preparation to which they have been 

 subjected. Naturally, indeed, tubes may be articulated, since 

 they are more or less short, and unite at intervals end to end 

 by their rectangular extremities ; they may further appear to be 

 articulated when the walls are broken through in consequence of 

 maceration, and the continuity of the tube is maintained by the 

 thickened juices of its interior; the tubes, again, may appear 

 in a state of expansion or of contraction because their diameter 

 varies considerably in their course — and they may be either full 



Ann. i^ Mag. N. Hist. Ser. 3. Volxa. 23 



