Olson : OBSERVATIONS ON GIGARTINA. 159 



A study of these pits showed them to be of the form of small 

 plates or rings, apparently one in each of the two adjacent cells 

 (Figs, ii and 13, PI. 9). When seen edgewise they appear as 

 two small plates narrower than the width of the cell wall, so that 

 the inner line of the cell wall appears to curve out to meet them. 

 Often the entire outline of one ring may be seen .and only part 

 of the other, which apparently lies beneath it. Again "the sec- 

 tion will lie so as to show both rings. 



Some sections, especially with the methyl violet, showed a 

 faint outline of cell contents just within the wall and in all cases 

 extending close up to the rings or pits. Careful observations of 

 this sort led to the opinion that these connecting pits uiust be of 

 the nature of the protoplasmic cell contents rather than the cell 

 wall. Schmitz confirms this opinion. Unfortunately the writer 

 did not have access to Schmitz's original article, but in George 

 Murray's Introduction to the study of Seaweeds, 1895, in the 

 chapter on Rhodophycese (which he states is based upon 

 Schmitz's papers) the following is found (p. 201): "The 

 plates stand in direct connection with the protoplasm lining the 

 cell wall and are, in fact, so coherent with it that they may be 

 regarded as transformed or rather differentiated protoplasm lo- 

 cally covering the pit. However it is probable that a thin layer 

 of protoplasm covers them in turn." 



All observations have gone to show that there is an intimate 

 protoplasmic connection between the contents of neighboring 

 cells. Zimmermann's Botanical Microtechnique was consulted 

 as to re-agents for testing these rings. 



The use of sulphuric acid and a mixture of iodine and potas- 

 sium iodide is recommended for cellulose walls giving a blue 

 color. This was used, but neither the cell walls nor the pits 

 showed any trace of blue staining. Cuprammonia was also 

 tried, but with no success. Some interesting results were ob- 

 tained, however, with the use of sulphuric acid. The sections 

 were first stained and then treated with the acid. Although the 

 acid at once destroyed the original color it was found better re- 

 sults were obtained than without first staining. A trial was then 

 made as to the strength of acid which would give most satisfac- 

 tory results, and it was found that treating sections prepared 

 as before described, with a 50 to 60 per cent, solution of the acid 

 produces at first no apparent effect beyond a slight swelling of 

 the cell wall. The sections were left mounted in the acid, and 



