The Life of the Fly 



jaded with their exertions, have died at a 

 higher or lower stage of the road. Lastly, 

 with yet another tube wherein the column of 

 sand measured sixty centimetres,^ I obtained 

 the liberation of only a single Fly. The 

 plucky creature must have had a hard struggle 

 to mount from so great a depth, for the other 

 fourteen did not even manage to burst the 

 lid of their caskets. 



I presume that the looseness of the sand and 

 the consequent pressure in every direction, 

 similar to that exercised by fluids, have a cer- 

 tain bearing on the difficulties of the exhuma- 

 tion. Two more tubes are prepared, but this 

 time supplied with fresh mould, lightly heaped 

 up, which has not the incoherence of sand, 

 with the attendant drawback of pressure. Six 

 centimetres of mould give me eight Flies for 

 fifteen pupae buried; twenty centimetres give 

 me only one. There is less success than with the 

 sandy column. My device has diminished the 

 pressure, but, at the same time, increased the 

 passive resistance. The sand falls of itself 

 under the impact of the frontal ran:n:cr; the 

 unyielding mould demands the cutting of a 

 gallery. In fact, I perceive, on the road fol- 

 lowed, a shaft which continues indefinitely 



^23.4 inches. — Translator's Note. 

 362 



