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524 



ME 





























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hypodermal tissue, collenchyma, tendrils (Bryonia, Cohaa, Cucu- 

 mis, Vitis), endosperm cells (occasionally). Moreover, by taking 

 proper precautions, lie claims to have found protoplasm also in 

 the xylem- and phloem-fibres of several plants. 



These views of Krasser and Wiesner have met with severe 

 handling on the part of Klebs * and Fischer t- Klebs holds 

 that, even if there be proteid in the cell- wall, which has not been 

 proved, there is no justification for the supposition that we 

 have to do with organized living protoplasm. He favours 

 Strasburger and Schmitz'sJ theory of the origin of the cell- 

 wall, viz. that the peripheral layer of protoplasm is directly 

 changed into cellulose; and as an example of the rapid way 

 in which this transformation takes place, he cites the membrane 

 around ejected plasma-masses of Vaucheria. This cannot be 

 living protoplasm, for, by contracting the latter in a 

 solution of syrup and staining with Congo-red — a dye which 

 is not taken up by protoplasm — we learn that cellulose has 



Low and Bokorny's § 



weak 



been formed. He also, by employing Low and Bokorny s 

 alkaline silver-solution method, which Krasser himself had par- 

 tially relied upon, finds that, if Krasser's application of the 

 method be correct, there is unmistakable evidence of protoplasm 

 in the wall of the pitted tracheides of young Maize plants, while 

 the other cells react very much less clearly ! Eischer believes it 

 impossible to distinguish proteid by micro-chemical means alone ; 

 he says that morphological and developmental facts must always 

 be adduced, and he submits Krasser's results with Bromeliaceous 

 leaves to very damaging criticism. He shows, too, that it is not 

 the presence of proteid which hinders the cellulose reaction in the 

 case of young membranes, but that time is required to stain them 

 blue with Schulze's solution. Also that in some cases (sections 



Nidulariu 



Millon 









He 



reagent after, as before, the action of a peptonizing fluid, 

 thinks it probable that not proteid, but some substance resulting 

 from direct destructive metabolism of proteids, probably Tyrosin 



Wiesner 



To 









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* Bot. Zeitung, 1887. t 



t Strasbursrer. Ueb. d. Bau und d_ \S 



Ber. d. deutsch. bot. Gesellsch. 1887 





* -n 



1880 



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