CELLULAR TISSUE. 19 



almost all those which we shall have to examine here- 

 after upon the organic nature of vegetables ; and it is 

 the basis of all discussion upon the use of these same 

 organs. We shall endeavour to explain it with as much 

 clearness as the difficulty of the subject will permit. It 

 is not easy to affirm, in a very positive manner, what 

 was the opinion of Malpighi ; and probably he had not 

 formed any decided one upon the subject : nevertheless, 

 the name of Utricle or Vesicle, wliich he has given to the 

 closed cavities, and most of the figures which he has 

 published, affijrd us grounds for presuming that he re- 

 garded each of them as a separate little body, furnished 

 with its own partitions, and simply adhering to or in 

 juxtaposition with the neighbouring bodies ; whilst, on 

 the contrary, Grew, in ginng to these same cavities the 

 names of Pores or Cellules, has more clearly indicated 

 that he considered them as cavities combined together 

 into a tissue or a texture, continuous in all directions, 

 of such a kind that each of them is separated firom its 

 neighbour by a single and simple partition. In accord- 

 ance with the opinion which Malpighi appears to have 

 entertained, Leeuwenhoeck seems to admit the existence 

 of distinct utricles bound together by intermediate fibres. 

 Hedwig and Mayer have considered the cavities as the 

 receptacles destined to receive the liquids, and have 

 admitted that many little vessels wind spirally upon 

 their walls. 



Treviranus and Kieser have maintained that vege- 

 tables are composed of vesicles more or less joined 

 together, separated by visible interstices, which they 

 have described under the name of Intercellular or 

 Intervascular Passages (meats intercellulaires ou in- 

 tervasculaires ) , PL 1, fig. 1, 3. Link has adopted 

 the same opinion, and says, that he has frequently seen 

 the cellules isolated, especially when he has subjected 



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