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in water, this drawn out while under the microscope, 

 the salt solution applied and the effect on the hair cell 

 wall watched, solution removed and water reapplied, 

 and the rapidity with which the cell regained its tumes- 

 cence noted. In these ways it was proved conclusively 

 that the cell wall of the hair offers little resistance to 

 the entrance of water. 



One more example from the first class may be 

 allowed, owing to its peculiarly beautiful adaptation, 

 anatomically, to the support of this assumed function of 

 the hair. The leaf of Alfredia cernua Cass, is about 

 15 by 30 centimeters in size, filzig on the under side, 

 immersed in water the surface between the veins shows 

 a bright silver color, which does not extend, howewer, 

 over the veins themselves, on removing it quickly from 

 the water, these are seen to be thoroughly wetted. The 

 hairs are of two kinds, those on the leaf surface between 

 the veins are like those first described, first a single 

 thin-walled cell, then the usual long dead cell. These 

 latter cells together from a thick filz over the surface. 

 The hairs on the veins have from five to seven large 

 living cells, averaging 100 mik. in diameter by 200 mik. 

 in length. The end cells which are very long, lie along 

 and across the veins having the appearance of spider- 

 webs and may easily by removed by the pincette without 

 injuring the filz below formed by the smaller hairs of 

 the leaf surface. As is well known, the veins project 

 a little from the under surface of the leaf making that 

 part of the leaf slightly convex. Were this a contrivance 

 to make use of the dew which collects on the under 

 surface of the leaf, no improvement could be suggested, 

 for the weight of the water would incline it toward the 



