22 



CELLULAR TISSUE. 



the Chara Vulgaris, and afterwards on that of other species. 

 Pouchct and Meyen have extended their observations to other 

 plants and succeeded in detecting a circulation in the Vales- 

 neria, Stratiotis, Potamogeton and in the hairs of the Inipa- 

 tiens balsamina, Vicia faba, (common bean) Cucumus sati- 

 vus, (cucumber) and many others. More recently the Chara 

 has been most minutely and laboriously examined by Datro- 

 chet. and the result of his experiments was read before the 

 Academy of Science on the 4th of December 1837, and pub- 

 lished in January 1838. We deem some points of his ob- 

 servations important in this place, that the student may have 

 a true idea of the constitution of a class of 



oecgcsipoooooj 



the cellular tissue. The Chara is an aqua- 

 tic plant of the tribe Muscoidiee, consisting 



i 



p' 





sion. 



of slender stems with a central tube sur- 

 6^ rounded b}^ numerous small cortical tubes, 

 all filled with a fluid with small globules 

 floating in it. The roots also are of the 

 same construction, and contain the same 

 kind of fluid, suspending like globules. The 

 tubes of the stem are lined on their inside 

 , with innumerable green eliptical globules 

 /o)^ placed end to end, which are disposed as seen 

 /.y^^ in fig. 8, in a highly magnified stem of the 

 ^^iii Chara, the spiral series being attached to 

 ■««««/ >/f -^''-^ ^j^g membranous tube by a very slight cohe- 



Figure 9, gives a transverse section of the Chara high- 

 q ly magnified, in which the cortical tubes 



are seen arranged in a circle around 

 the central tube, generally eighteen in 

 number. By removing the cortical tubes 

 with care and applying the microscope, 

 we observe the floatins" jrlobules follow- 

 'p^^! ing with perfect regularity the direc- 

 ion of the spirally arranged globules 

 ^^■^ attached to the tube. The ascending 

 tTliF current when it arrives near the node, 

 turns and forms a descendino; current on 

 the opposite side following with equal regularity the green 

 globules. Between these two currents there is a line destitute 

 of green globules, and under which the fluid does not circu- 

 late, and which is called the line of repose. Figure 8 will 

 give the student an accurate idea of these appearances. If 

 the green globules make accidentally any sinuosities the float- 

 ing globules follow these sinuosities. If the green globules 



