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Show 160 WEIGU'l' OF EAR'l'II CnAP. liT. founded on the numbers found in a garden, and IIensen believes that worms are here twice as numerous as in corn-fields. The above result, astonishing though it be, see1ns to me credible, judging fr01n the nurnber of worms which I have sornetiJnes seen, and frorr1 the number daily destroyed by bir d~ without the species being extenninated. S01ne barrels of bad ale were left on Nir. Miller's land,* in the hope of making vinegar, but the vinegar proved bad, and the barrels were upset. It should be premised that acetic acid is so deadly a poison to worms that Perrier found that a glass rod dipped into this acid and then into a consideraLle body of water in which worms were immersed, invariably killed them quickly. On the nlorning after the barrels had been upset, ''the " heaps of worms which lay dead on tlw ''ground were so amazing, tl1at if Mr. Miller "had not seen them, he could not have "thought it possible for such numbers to " have existed in the space." .r\.s further evidence of the large number of worms which live in the ground, Hensen states that he * See Mr. Dancer's paper in ' Proc. Phil. Soc. of Mancheste r,' 1877' p. 248. CHAP. III. BROUGHT UP BY WORMS. 161 found in a garden sixty-four open burrows in a space of 14:\- square feet, that is, nino in 2 square feet. But the burrows are sometimes much more numerous for when dio-O'ino• ' b b 0 1n a grass-field near Maor Hall, I found a cake of dry earth, as large as my two open hands, which was penetrated by seven burrows, as large as goose-quills. Weigltt ~f the earth eJected from a single burrow, and f rom all the burrows witltin a given pace.~ With respect to the weight of the earth daily ejected by worms, flensen found that it amounted, in the case of some worms which he kept in confinement, and which he appears to have fed with leaves to only 0·5 gram, or Jess than 8 grains p' er diem. But a very much larger amount must be ejected by worms in their natural state, at the periods when they consume earth as food instead of leaves, and when they arc making deep burrows. This is rendered almost certain by the following weights of the castings thrown up at the mouths of single burrows; the whole of which appeared to have been ejected within no long time, as was certainly the case in several instances. The M |