1902.J KRAEMER — COXTINUITY OF PROTOPLASM. 179 



and represent tracts or channels through which liquids are distributed 

 from cell to cell. 



Furthermore, attention should be directed to the fact that the 

 preparations of both the starch grain and cell wall showing the 

 colored lamellce and striae, as already described, are permanent only 

 in Canada balsam and are ephemeral in glycerin or glycerin jelly. 



Finally, it may be stated that all authors since the appearance of 

 Gardiner's work* have fallen into the error of supposing that a 

 certain aniline dye could be regarded as a differential stain for pro- 

 toplasm, whereas the fact of the matter is that many colloidal car- 

 bohydrates, as mucilage and pectin, and oils and other substances 

 as well, take up these stains. And in this connection we may ask, 

 If the substance in the cell wall which takes up the stain is proto- 

 plasm, what is it in the starch grain? 



Bibliography. 



1 ScHLEiDEN : Grundzuge der wissenschaftlichen Botanik, i. Aufl., 1842-1843. 



2 HoFMEiSTER : Die Lehre von der Pflanzenzelle. 



3 Sachs: Vorlesungen liber Pflanzenphysiologie, 1882, p. 102. 



* Strasburger : Ueber den Bau und das Wachsthnm der Zellhaute, 1882, p. 246. 

 ^ 5 Naegeli : Mechanisch-physiologische Theorie der Abstammungslehre, 1884, 

 p. 41. 

 6 Hartig : Botati. Ztg., 1854, p. 51. 



' Thuret and Bornet: Etudes phycologiques, Paris, 1878. 

 8 Fromann : Sitzber. der Jenaischen Gesellschaft fur Medicin und Naturwis- 



sensch., 1879, p. 51. 

 8 Tangl : Vnngsh.Q\m's yahrbilcher filr wissenschaftliche Botanik, 'Qz.yxd, 12, 



1880, p. 170. 

 10 Gardiner: Arb. d. bot. Inst, zu Wurzburg, Bd. Ill, 1884, P- 52. 

 ^^ Kienitz-Gerloff: Bot, Ztg., 1891, p. i. 



Schaarschmidt : Botanisches Centralblatt, xviii, 1884, p. 265. (See also 

 A^ature, xxxi, 1885, p. 290.) 



Explanation of Plates. 



Plate XXI. 



Fig. I. Potato starch grain with point of growth and alternate Iamell::e liaht in 

 color. 



* Gardiner states that « All experiments made with the view of attempting to 

 detect the presence of protoplasmic filaments in the cell wall when the cell was 

 normal and intact met with but little success, so that in investigating the subject 

 of protoplasmic continuity the method of swelling the cell wall and subsequently 

 staining with a dye which was found to especially stain the protoplasm was 

 adopted." 



