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living cell, sometimes narrows abruptly down to 6 mik. 

 in diameter, is extremely thick-walled, showing only a 

 small lumen throughout its entire length ; sometimes it is 

 thin-walled, flattened, and pressed together. These cells 

 lie mostly horizontally across the leaf surface and are 

 coiled and matted together into a thick filz. 



Between the living cells standing at right angles to 

 the surface are the raised stomata, thus surrounded by 

 an atmosphere which may vary considerably from that 

 surrounding the leaf itself, both as to temperature and 

 amount of moisture contained. The consideration of this 

 peculiarity of the stomata, however, we will leave for 

 the present, to be taken up by itself. 



In order to ascertain the ability of the leaf to ab- 

 sorb water, it was allowed to wilt till no trace of tur- 

 gescence could be seen, the leaf when held by the 

 petiole could no longer sustain its own weight but hung 

 limp from its support. In this condition it was lightly 

 brushed with a hair brush containing water, none being 

 allowed to come in contact with it except on the hairy 

 surface. The water was sometimes applied in this way, 

 sometimes the leaf was immersed in water and instantly 

 removed, sometimes allowed to remain with the hairy 

 surface in contact, the petiole or broken surface being 

 carefully protected by a wax covering. 



The Helichrysum leaf, after having water applied 

 with a brush and lying one half hour, became fresh, 

 stiff, and turgescent. No attempt was made to ascertain 

 the exact amount of water taken up, owing to the ex- 

 treme difficulty of obtaining accurate results. The che- 

 mical balance offers, perhaps, the most practical method 

 but there is no means of determining exactly how much 



