152 F. 0. BOWER. 



tinuity has actually been observed by Tangl' in the endosperm 

 of certain seeds, and by Gardiner ^ in the pitted cells of the 

 pulvinus of Mimosa, Robinia, and Amicia. Again, Fromman^ 

 states that he has been able to observe, in various cases, a 

 continuous network extending from the protoplasm into the 

 cell wall. 



Such observations as these do not harmonise with the view at 

 present held of plasmolysis, which is derived mainly from the writ- 

 ings of H. de Vries.^ According to his descriptions of the process 

 of plasmolysis (1. c, pp. 37 — 39, and esp. pp. 47, 48), the proto- 

 plasmic body would appear to separate with a " smooth surface^' 

 from the cell wall on treatment with the plasmolysing solution, 

 and, when the solution is strong enough, to be completely iso- 

 lated from the cell wall. Hence is derived the idea, which is, 

 it is true, more often tacitly understood than directly expressed 

 in words, that the smooth surface of the protoplasmic body is 

 merely in apposition with the cell wall, and not more closely 

 connected. 



The observations detailed below will tend to show that results 

 obtained by plasmolysis do not disagree with those obtained by 

 the direct observations of the above-named authors, i. e. that 

 the connection of the protoplasmic body with the cell wall is 

 very close. 



Before entering upon the description of my own observations' 

 it would be well shortly to review the chief sources from which 

 our present information on the subject is derived. 



V. Mohl, in his treatise on the vegetable cell, speaking of 

 the " primordial utricle," remarks that " it usually adheres 

 firmly to the cell wall."'^ His results were, however, obtained 

 for the most part by treatment with acids, &c. 



' Pringsh., ' Jahrb.,' vol. xii, p. 170. 



• 'Quart. Journ. Micr. Sci.,' Oct., 1882 ; 'Roy. Soc. Proc.,' Nov. 11, 1882. 

 3 'Beob. iJber Structur und Beweg. d. Protoplasma der Pflauzeiizellen.* 



Jena, 1880. 



* 'Unters. iiber die Mechanischen Ursachen der Zellstreckung.' Leipzig, 

 1877. 



5 V. Mol>l, ' Vegetable Cell,' Englisli translation, p. 37. 



