206 The Anatomy of Plants BOOKII 



cylinder, as occurs in some stems and in all roots, the 

 fundamental tissue takes the form of cortex only.' 



Sachs criticized Hanstein's theory of the cortex, saying 

 the layer is ' altogether indefinite and indefinable we speak 

 e. g. of cortex in Thallophytes in quite a different sense to 

 what we do in Vascular plants ; the cortex of Monocotyle- 

 dons is something different from that of Conifers and Dico- 

 tyledons ; in the latter the cortex has quite a different 

 signification in young and in older parts of stems.' 



The physiological bent of Sachs' mind showed itself 

 further in the subdivision of his several tissue systems. 

 Among others he recognized succulent tissue, ' the cells of 

 which during the life of the organ remain filled with the 

 chemical products of the vital activity of the plant ' ; 

 laticiferous tissue, glandular tissue, &c., each division being 

 based on function. 



Sachs' scheme met with very strong criticism from the 

 pure anatomists. De Bary wrote of it as follows : 



' Sachs, in the exposition of the anatomy of the higher 

 plants, starts from the definition of three systems of tissue, 

 which he terms Dermal, Fascicular, and Fundamental 

 tissue. Under the first term he includes those tissue-forms 

 which limit externally such plants as have their cells aggre- 

 gated in three dimensions of space, as a matter of fact 

 Epidermis and Periderm. His Fascicular tissue corre- 

 sponds in the main to the vascular system. The name 

 Fundamental tissue includes what remains after the separa- 

 tion of the other two. However much this distinction may 

 be fitted to guide beginners, still, in my opinion, it does 

 not answer its purpose, which is to serve as a basis for 

 a uniform exposition of the various differentiations of plant 

 tissues. For the names Dermal and Fascicular tissue indi- 

 cate in vascular plants systems of tissue which are positively 

 characterized by definite tissue-forms ; but the name Funda- 

 mental tissue implies the remainder, and this may just as 

 much consist of different positively characterized tissue- 

 forms and tissue systems, which are equivalent to the dermal 

 and fascicular systems. But if it is necessary, in the 



