CHEMICAL CLOCK 165 



passing leaves an indelible trace in us, just as in a motor-car 

 every turn of the wheels registers in the speedometer a figure 

 which is added on to the preceding figures. Nature does not 

 dispose of mechanical systems such as speedometers, but the 

 result is approximately the same. It seems difficult to call 

 upon another procedure for the explanation of the existence 

 of this type of memory, for there can be no question of a 

 mechanism identical with that of our sense memory which 

 retains and easily evokes events registered by our senses, but 

 without respecting the dimensions of time. A proof of this 

 is given by dreams in which the scale of time is often strangely 

 contracted. But, when the registration of the flight of time 

 is concerned there can only be question of a passive, sub- 

 conscious memory, of physico-chemical or chemical nature, 

 which would be only one of the manifestations of ageing, and 

 the very foundation of our notion of duration. 



Should this really be the case we would have answered the 

 objection, for we would have demonstrated that the fact of 

 admitting an estimation of the apparent length of a year, based 

 on the comparison of the number of years gone by since birth, 

 would imply a subconscious totalizing system which might 

 well be one of the psychological manifestations of the physio- 

 logical and chemical transformations introduced by age. 

 Instead of eliminating the objection we would, on the contrary, 

 have incorporated it into the totality of phenomena which 

 are correlative to ageing. But the whole question would still 

 remain hypothetical. 



To confirm the reasoning as a whole or, at least, bolster up 

 its probability by facts, the two series of calculations used to 

 express quantitatively the apparent shortening of duration of 

 one year, based, the first, on the coefficient A of physiological 

 activity, the second, on the value of a year expressed in frac- 

 tions of the age of a man, should coincide at least approximately. 

 If only the order of magnitude of the shortening were the 

 same in both cases, it would supply an impressive argument 

 in favour of the thesis expounded in this book. 



Nothing is easier than to confront the two hypotheses. If 



