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openings, " it is necessary to be able to determine the rate of 

 transpiration and the size of the stomatal openings independently 

 at the same instant of time. . It is obvious that we may neither 

 judge the rate of transpiration from the size of the openings, nor 

 the size of the openings from the rate of transpiration. How to 

 do this was the difficult task, but with a sufficiently small error, 

 this was done in the following manner : 



" It was found that the stomata of certain, and probably many, 

 plants may be fixed in the form in which they are found in life 

 by tearing off the epidermis and plunging it into absolute alcohol. 

 The distortion of the stomata caused by the tearing is only tem- 

 porary, the guard cells recovering their form just as a rubber 

 ball does when it has been released from pressure. The alcohol 

 extracts the water from the cell-walls, thus rendering them rigid, 

 and this it does so rapidly that they do not have a chance to lose 

 the water contained within the protoplast while the walls are still 

 pliable, a process which would result in closure." 



Many series of experiments, mostly with the ocotillo, Fojigtcieria 

 splendens, under varying conditions as to light, heat, humidity, 

 etc., have led Professor Lloyd to the following conclusions : 

 "With little or no movement in the stomata, and therefore with 

 little change in the size of their openings, wide fluctuations in the 

 rate of transpiration may and do occur ; " and further, the evidence 

 now in hand on the plants studied does not support the view that 

 stomata are regulators of transpiration. " These are not markedly 

 desert types as far as the stomata are concerned, and the amount 

 of water-vapor which may escape through one type of stoma per 

 unit of time may be greater or less than that which may escape 

 through another type. The structure of the stoma, as that of 

 other organs, may indeed explain why some plants are able to 

 get along in the desert, and others not. Stomata of a given form 

 may act as a dampener on transpiration, just as, using an analogy, 

 the mute in a cornet reduces the amount of sound which emerges 

 from the instrument. But the mute does not regulate the sound, 

 causing now more and now less in successive intervals of time. 

 In this sense, also, stomata cannot be said to regulate the flow of 

 water-vapor from the leaf Nor do they ' anticipate ' wilting, the 



