NATUllAL KHYTIIM. 149 



tion, which preponderance is not much modified 

 by adding the next succeeding proportion, thus, 

 frlris = tlT- Consequently, the organism may faiily 

 be supposed to have entered upon the next pro- 

 longed period of rest (viz. 185 seconds) with a large 

 balance of reserve power; so that when to this large 

 balance there was added the further accumulation 

 due to the further rest of 185 seconds, we are not 

 surprised to find the next succeeding swimming 

 bout comprising the enormous number of 894 

 pulsations. But this great expenditui'e of energy 

 seems to have been somewhat in excess of the 

 energy previously accumulated by the prolonged 

 rest, for this unusual expenditure seems next to 

 have entailed an unusually prolonged period of 

 exhaustion. At any rate, it is plainly observable 

 that the next succeeding proportions are greatly in 

 favour of repose; for it is not until 360 seconds 

 have elapsed, with only twelve pulsations in the 

 interval, that er.ergy enough has been accumulated 

 to cause a moderate bout of thirty pulsations. But 

 next another long and sustained pause of 240 

 seconds supervenes, and, the animal being now fully 

 refreshed with a large surplus of accumulated 

 energy, the next succeeding swimming bout com- 

 prises two hundred pulsations. Lastly, there suc- 

 ceeded sixty seconds of rest, and here the observa- 

 tion terminated.* 



* If the reader takes the trouble to ascertain the average pro- 



portiou between the number of pulsations and the seconds of rest 



in the first observations as far down as the first long pause, viz. 



as above stated, m, and if he then balances the succeeding income 



11 



