36 CLASSIFICATION OF CELL TYPES, TISSUES, AND TISSUE SYSTEMS 



tious "llaiiclbucb der PHaiizenaiiatomie" which treats of the 

 varied phases of anatomy in monographic fornL Linsbaiier, as 

 the original editor, states in the first volume of this encyclopaedic 

 Avork, that, aside from certain disagreement in details, the prin- 

 ciples of Haberlandt's physiological anatomy will be adopted. 

 In this same volume, an able and penetrating discussion of the 

 various concepts and classifications of tissues is given by Lunde- 

 gardh (1922). This author, while agreeing in principle witli 

 the anatomieo-physiological method of classification, emphasizes 

 the need for a cantions and critical api)roach to the problem, 

 since "the physiological-anatomical systems only indicate the 

 uoi-mal combination of structure and function and obviously do 

 not permit of any teleological conclusions as to the method of 

 their origin." Lnndegardh {op. cif., p. 175) i)roposes the fol- 

 lowing anatomieo-physiological conspectus of tissue systems, viz. : 



1. The Coherent Tissue Systems (comjiosed of c(Hi1i uncus 

 cell aggregates). 



A. The Formative or IMeristematic Tissues. 

 P.. The Mature Tissues. 



1. Systems with dynamic j'um'tions, e.g., assimilation, 

 respiration, storage, absorption, etc. 



2. Systems with static functions, e.g., protection, nie- 

 ciianical support, etc. 



II. The Disperse Systems (composed of isoJuial cells or cell- 

 groups distributed as "islands'" in the midst of various 

 ' ' coherent systems ") . 



A. Stomata (i.e., guard and accessory cells). 

 15. Organs of Perce])tion. 

 ('. Peproductive Apparati. 



1). Idioblasts (e.g., isolated stone cells found in lli(> nieso- 

 pliyll of certain foliage leaves such as Camellia). 



Two |)i-in('ipal objections have been advanced against Ilaber- 

 landl 's sclicnie of classification and the fundamental assumptions 

 upon which any anatomieo-physiological system is based. First 

 of all, Haberlandt's system is constructed with respect to the 

 nature of the "principal function" of each tissue system. IIow- 



