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classes. In answer to this, it must be remembered that 

 in no case is it claimed that the only function of the 

 filz is to draw in water from the atmosphere, or to lessen 

 the transpiration. In all the examples of this class there 

 may exist a need for protection of some other nature 

 than that against drouth. In order to meet this, a filz 

 may be necessary of such thickness that transpiration 

 would be too much impeded without the intervention of 

 the raised stomata. As before intimated, several facts of 

 different kinds, aside from the anatomy of the hair, point 

 to some other function than that of regulating the water 

 supply. Many of these plants originate from countries 

 not remarkable for lack of water, nearly all of them are 

 of woody texture, the leaves growing on stems removed 

 from the earth's surface ; lastly all the experiments tried 

 failed to prove that any considerable amount of water 

 was taken up by the hairs. 



On the other hand it is claimed that even here, in 

 these more questionable examples, there is a strong 

 probability that one function of the filz is to conduct 

 moisture to the epidermal surface by means of its capil- 

 lary passages, where it may be taken into the leaf texture, 

 though of course in much smaller quantities and much 

 less rapidly than where the surface is increased by 

 large living hair cells. 



Such examples as Spiraea, where the hair cells were 

 found always to contain diluted air, and where the mem- 

 brane offered so little resistance to the entrance of water 

 from outside, indicate the reciprocal play of certain forces, 

 more thorough investigation and more fortunate methods 

 of experimenting may make clear how these forces act, 



