60 
Walter Gardiner. 
This phenomenon evidently points to the f'acl that the substance of the 
pil-closing-meinbrane and of the layers iramediately surrounding the pit- 
cavity arc more resistent than the resl of the cell-wall. Exacllv the samc 
thing was noticed by Strasburgeii ') who proved that by caulious treatment 
of a seetion wilh dilute Sulphuric acid or vvith vveak Arurnoniacal oxide of 
Cop]>er the middle lamella and the pit-closing-meinbrane remained while 
the rest of the cell-« all suffered Solution. With stronger Solutions of the 
ahove rcagents he likewise found that the pit-membrane also disappeared. 
Evidently tho fact ol not using some staining reagent prcvented him froin 
demonstrating that the sides of the pits, as well as the pit-membrane ilself, 
arc more resistent than the general cell-wall. 
Exactly the same phenomena are observed when a seetion after cau¬ 
lious treatment with Sulphuric acid is stained with Methyl violet. In the 
case of Methylene blue the protoplasm is not coloured, but when Methyl 
violet is used a deep staining of that structure occurs, the tint of which is 
the same as that of the bottoms and sides of the pits: for whereas the general 
cell-wall assumes a violet colour, the protoplasm, the pit-membranes and 
the pit sides appear of a deep purple. Now since protoplasmic processes 
froin the main protoplasmic mass may project for some distance into the 
swollen pits, when such a stained seetion of pitted tissue is examined it 
appears as if therc were in any two contiguous cells, filaments of protoplasm 
of a purple colour traversing the thiekness of the violet coll-walls by means 
of the pits, and thus establishing a direct continuity of the protoplasm from 
cell to cell. However after prolonged treatment with dilute giycerine this 
purple colour dissolves from the pits, and the protoplasmic processes are 
left clearly seen and may or may not be the means of establishing a con- 
linuily between the cells. As in the case of Methylene blue so also here a 
more lengthy treatment of the tissue with acid will swell up tho pit-mem¬ 
branes, and when in that condition the pits will assume the same colour as 
the rest of the cell-wall 1 2 ). 
II. Observations. 
Ilaving thus described my melhods at some lenglh, 1 can now proceed 
to give an account of the results I obtained with pulvini and other organs 
in which a continuity of the protoplasm was shown to exisl, and as the 
principal object of the paper is to study the relation which exists between 
protoplasm and cell-wall. 1 shall only quote such anatomical and physio- 
Iogical details as arc necessary for the proper understanding of tho organ 
in question. 
1) Strasbürger. ‘Bau und Wachsthum’. Pages16&22. 
2) Whetlier this resistent cliaracter of the pit-membrane is duo to tho fact that it 
contains protoplasm in its structure must for tiio present be left an open question. 
