the Pitied Tissue of Plants. 101 



ized in drawing from the above considerations the following 

 conclusions : — 



1st. That the uniform dotted arrangement on the walls of 

 the vasa spiroidea simply results from the pressure of the sur- 

 rounding parts alone. 



2nd. That the supposition of the starch particles being 

 analogous in function to the blood-globules is unfounded; and 

 that the black line seen upon the starch particles cannot, and 

 does not, perform any such office as has been supposed. 



3rd. That the imagined secondary formations from the 

 blood-corpuscles are really misinterpreted appearances ; not 

 vital but physical*. 



9 St. John's Square, Dec. 1842. 



EXPLANATION OF PLATE IV. 



Fig. 1 . Vessel from Typha latifolia, showing the dots extending nearly across 

 the face of the tube from the pressure of one large similar tube or 

 cell. 



Fig. 2. Origin of beaded appearance, i. c. the fibres cut across and project- 

 ing. (T. latifolia.) 



Fig. 3. Same as 1 and 2. On the tube b two smaller tubes have pressed, 

 whilst opposite a only one has existed. (T. latifolia.) 



Fig. 4. Tube from Arundo Phragmites, showing the results of the pressure 

 of two of different sizes on one tube. 



Fig. 5. From Aspidium Filix mas, a transverse section showing the dots op- 

 posite the convexity of the projecting cells. 



Fig. 6. Projecting teeth, leaving spaces between them corresponding to the 

 dot. (T. latifolia.) 



Fig. 7. Section of tube of the same, showing the dot to be formed of mem- 

 brane only. 



Fig 8. Ring of an annular duct of Arundo Phragmites, which has been pressed 

 upon by three surrounding cells orvessels, thickened at the bendings. 



Fig. 9. Tube from Pteris Aguilina, showing the impression of one tube upon 

 another, and the dots on that portion corresponding to its breadth. 



Fig. 10. From Typha, showing adhering portions of surrounding cells or 

 vessels. 



Fig. 11. Section of stem of Typha : cells similar to those at a, pressing upon 

 and producing large dots ; those similar in size to b, b produce 

 smaller ones, as at c. The interruptions to the regular arrangement, 

 as at e, are caused by the abrupt terminations of the surrounding 

 tubes, leaving spaces. 



Fig. 12. Tube from Typha, showing the loose fibres bent and thickened at 

 the joints. 



Fig. 13. Diagram showing the spiral fibre pressed upon by surrounding ves- 

 sels or cells, first stage. 



Fig. 14. Second stage, a, a, a, a, bendings of fibres corresponding to inter- 

 cellular or intervascular spaces ; b, pressing cells. 



Fig. 15. Muscular fibre, showing what might be interpreted into an appear- 

 ance of interlacing fibres when not quite in focus. (Bostock, Barry 

 in Trans, of Royal Soc.) 



* 1 believe the tissues to be all reproduced by the transudation of the liquor 

 sanguinis through the walls of the capillaries; and that no blood- globules can 

 ever leave the capillaries unless their walls he ruptured, which must always 

 be the case in hemorrhage by " simple exudation." 



