134 PLANT RESPONSE 



recorded on a fast-moving drum, using the style of Datura 

 alba, I find that the height of the normal response was eleven 

 divisions, and complete recovery took place in one minute 

 and a quarter. During the first period of exaltation, after 

 the application of alcohol, the height of the response was 

 increased to sixteen divisions, that is, practically half as 

 much again. But the period of recovery was protracted to 

 four and a half minutes, or nearly three times the period of 

 normal recovery. These considerations will fully explain 

 the series of responses under the continued action of alcohol- 

 vapour, given in fig. 71, where {ci) shows normal response, 

 {h) the immediate and transitory exaltation, and {c) — which 



• 



Fig. 71. Efiect of Vapour of Alcohol 



{a) Normal response ; [h) immediate temporary exaltation on introduction 



of alcohol ; {c) subsequent depression. 



was taken after fifteen minutes' further application — the 

 diminished responses in which the contraction remainders 

 are a marked feature. On blowing off the alcohol-vapour, 

 however, and substituting fresh air, the tissue is found to 

 recover slowly its normal excitability. If, instead of alcohol- 

 vapour, dilute alcoholic solution be applied, the depressing 

 effect is immediate and very great. 



Effect of ether. — We now pass on to the question of the 

 action of the anaesthetic agent, ether. This produces a relaxa- 

 tion so great as to be incapable of proper representations 

 within the limits of the diagram (fig. 72), where it is merely 

 indicated by the dotted line. It is to be remembered that 

 contraction is shown by lines upward, and recovery, or 



