818 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



A. GENERAL, including the Anatomy and Physiology 

 of the Phanerogamia. 



a. Anatomy.* 



Structure of the Cell-walLf— Prof. J. Wicsner records some very 

 important observations on this subject. 



Tho first deposition of cell-wall consists entirely of protoplasm, 

 and as long as the cell-wall is growing it contains living protoplasm 

 (dcrmatoplasm), but this is only visible to tbe Microscope when it 

 occurs in broad tracts destituto of cellulose, and then penetrates tho 

 ontire wall, as was first observed by Tangl. 



The structure of the cell-wall is, not only at its first origin, but 

 always, reticulate, corresponding to that of tho protoplasm from wbich 

 the cell-wall is always produced. The principal mass of a growing 

 wall consists of small round organized structures, dermatosomes, 

 formed from microsomes of tbo protoplasm or plasmatosomes, united 

 by delicate strings of protoplasm as long as the cell- '.vail is growing. 

 Out of these strings are formed new plasmatosomes and finally der- 

 matosomes, and on this depends the growth of the wall, which is 

 therefore essentially intercalary. The dermatosomes cannot, as a 

 rule, be directly observed in the cell-wall, but become visible when 

 the strings which connect them arc absorbed or broken. This can be 

 effected by various means, best by chlorine-water ; also by treatment 

 with a 1 per cent, solution of hydrochloric acid, with potash-ley, by 

 drying at 50-60° C, or by pressure. 



Mature dermatosomes are destitute of albumen, lifeless, but 

 capable of swelling. The water is contained in the cell-walls in two 

 forms : as " water of swelling " in the dermatosomes, and as capillary 

 water of imbibition between them, and enveloping the strings. The 

 union of the dermatosomes within a cell-wall is stronger than between 

 those of two adjoining cells. A loose framework of fibrillar compara- 

 tively easily soluble in reagents divides the so-called middle lamella 

 into two pellicles, so that each cell has its own outer lamella. The 

 cell-wall is properly neither fibrillar nor lamellar, but, according to 

 the arrangement of the dermatosomes, is stratified in the direction of 

 the threads, or fibrillar, or both, or apparently homogeneous. The 

 optical differentiation of the layers or fibrillar of the cell-wall is 

 brought about by the regular alternation of dermatosomes and sub- 

 stance of the framework. 



This occurrence of albuminous substances in the living cell-wall 

 explains its chemical nature and metamorphoses better than the 

 current theory, according to which cellulose is the first product in its 



* This subdivision contains (1) Cell-structure and Protoplasm (including the 

 Nucleus and Cell-division ; (2) Other Cell-contents (including the Cell-sap and 

 Chlorophyll); (3) Secretions; (4) Structure of Tissues; and (5) Structure of 

 Organs. 



+ SB. K. Akad. WiflB. Wien, Jan. 14, 1886. See Bot. Ccntralbl., xxv. (1886) 

 p. 353. 



