124 Mr, Paget^ on the Chronometry of Life, [April 8, 



Holland Cereopsis-goose has bred at the Zoological Gardens every 

 February for five or six years.* Among migratory birds, also, it has 

 been observed that when they are kept in confinement, and removed 

 from all the circumstances that might be supposed to induce or 

 necessitate their journeys, they yet become restless at the return of the 

 season for their migration. 



In these and the like facts there appear indications of a chrono- 

 metry in the organic processes of warm-blooded animals, which corre- 

 sponds with that of the seasons, but is essentially independent. And, if 

 it be so, these might form a group of facts, in addition to those of the 

 diurnal variations of the organic processes, in which vital changes are 

 set to the same rules of time as changes of the surface of the earth, yet 

 have their own proper laws ; and concerning which it might be said, 

 that the cycles of life, and of the earth, do, indeed, correspond, but 

 only as concentric circles do, which are drawn round one centre, but 

 are not connected, except in design and mutual fitness. 



But, however this might be, all the instances of time-regulation 

 cited in the discourse (all being examples of large groups of facts), would 

 seem sufficient to prove, that the observance of time in organic pro- 

 cesses is as exact and as universal as that of any other measure ; that 

 each species has a certain time-rate for the processes of its life, variable, 

 but not determined, by external conditions ; and that the several phe- 

 nomena commonly studied as the periodicities of organic life, are only 

 prominent instances of the law which it was the object of the discourse 

 to illustrate. 



[J. p.] 



* Mr. Sclater, to whom the speaker was indebted for this fact, supplied also 

 dates which tend to prove that the Australian parakeets, in this country, breed less 

 often in December than in the months from May to September, inclusive ; but even 

 a minority of instances of the observance of times, and a general tendency towards 

 it, when the force of such external conditions as those of the seasons is strong 

 against it, is good evidence that inherent properties are the mainsprings determining 

 the rates of life. 



