404 3Ir. Win i am Bat p. Hardy [April 6, 



solution of 1 part of spirit in 5,000 to 10,000 of water. In the 

 effect produced there is the touch of nature which makes the whole 

 world kin. The periods of depression were wiped out. The curve 

 of vitality no longer showed the ominous recurrent depressions. At 

 the same time the rate of growth and division — that is to say, the 

 physiological activity — was increased by as much as 30 per cent. 



Something of the same effect is produced by strychnine, but there 

 is a remarkable and significant difference in the fundamental action 

 of the two drugs, for whereas the beneficial effect of alcohol endures 

 after the drug ceases to be administered, that of strychnine does not. 

 Alcohol, as Calkin says, in spite of the prodigiously increased rate of 

 living, " exacts no physiological usury," it is beneficial in its after 

 effects. Strychnine is harmful in its after effects ; the onset of decay 

 and death is hastened. 



What significance are we to attach to artificial rejuvenescence ? 

 There are two possibilities. The chemical agent employed may either 

 add something which is missing or diminished in the chemical make- 

 up of the protoplasm, or it may restore a physical state. The former 

 implies that the chemistry of the growth process is imperfect : the 

 process of converting non-living to living matter is subject to inac- 

 curacies — inconceivably small it is true, since they need to be magni- 

 fied to the 170th power of 2 before they destroy the working of the 

 machine — but cumulative from generation to generation. I incline 

 to think that senile decay is due not so much to such a chemical 

 insufficiency as to the wearing out of a physical state, of a 

 "potential." 



Consider a special case. Thirty minutes' immersion of an 

 individual paramoecium in very dilute solution (1 part of salt in 

 1,000) of potassium phosphate was found to restore vitality, and the 

 effect persisted for 282 generations. Now, in this case the restora- 

 tion and maintenance of the " vital potential," as Calkin calls it, 

 cannot be due to the presence in the individuals of a trace of the 

 salt, for each generation would halve tlie amount, so that as early as 

 the twentieth generation less than a millionth part would be left for 

 each individual. One is therefore driven to believe that the salt acts 

 by restoring a state which, in the absence of natural or artificial 

 rejuvenescence, wears out in about 170 generations. 



The continual flux of energy and of matter which seems to be 

 necessary to the maintenance of life implies a high degree of mole- 

 cular mobility. It is possil)le that living matter, like all other forms 

 of matter, tends to come into equilibrium with its surroundings, and 

 to attain a condition of too great stal)iUty. To restore it the living 

 substance needs .stinuilating at intervals, just as a coherer needs 

 tapping after each electric wave lias })assed, in order to restore its 

 particles to the non-conducting position. Tliese are \'ague possi- 

 bilities, l)ut pliysical science furnishes a case so suggestively akin to 

 artificial rejuvenescence as to merit description, 



