314 WALTER GARDINER. 



reticular protoplasm may enter into the structure of cell mem- 

 rane to a greater or less extent." 



Briefly stated, the principal facts involved in these state- 

 ments are : that open passages of a very appreciable size are of 

 very frequent occurrence in the common cell wall. That chlo- 

 rophyl corpuscles and protoplasmic reticula occur embedded in 

 its substance. That the intercellular spaces may contain gra- 

 nules and nets. That these nets and reticula of protoplasm 

 may be traced into the cell wall, and are particularly clearly 

 defined in the case of epidermal cells, running from the cell 

 lumen out into the cuticle. 



With all deference to Professor Frommann, I cannot but 

 think that every one of these statements would be received 

 with some surprise by almost any botanist who is at all 

 acquainted with the histology of tissues. 



I have investigated in as careful a manner as possible 

 the leaves of Rhododendron ponticum and Dracaena 

 Draco, in order to give Professor Frommann's results a fair 

 test. Transverse and longitudinal sections, as well as sections 

 parallel to the leaf surface, were examined in water, in cell sap, 

 and in dilute glycerine. Both fresh material and that preserved 

 in picric acid and absolute alcohol, were made use of. Iodine, 

 Chlor. Zinc. lod., and hsematoxylin, which latter Schmitz ^ so 

 successfully employed in liis researches on the structure of 

 protoplasm, and the nucleus, were used as staining reagents. 

 Professor Frommann used expressed cell sap, sugar solution, 

 and dilute glycerine as fluids for mounting his preparations, 

 and employed methyl green as a stain ; but since he expressly 

 states that the staining due to this reagent was confined to the 

 nucleus, and did not afl'ecl the nets and reticula, one must con- 

 clude that most of his observations wore made upon pre- 

 parations which were simply mounted in the fluids before 

 mentioned. 



1 do not intend to enter into detail with regard to the subject 

 of the intimate structure of the proto])lasm. Suffice it to say 

 that in a great measure my results agree with those of Pro- 

 I Schmitz, ' Sitzbcr. d. niodcrrlmin Gos. in Bonn,' 1879. 



