766 BR JAMES BUCHANAN YOUNG ON THE 



In seventeen of the samples, moulds were specially investigated, worts-gelatine being 

 used as the culture medium. I never found moulds present in any sample taken at a depth 

 exceeding 5 feet from the surface. Those found were Mucor mucedo and Penicillium 

 glaucum, the former exceeding the latter in number in most samples. In several 

 instances I also observed a white mould resembling a mucor. I was never, however, 

 able to get it in a stage of sporulation. 



Turning now to the results of the purely chemical examination of the various samples, 

 we find that the surface layers of both ordinary and graveyard soils always contain a 

 considerable amount of organic matter, and that the amount of organic nitrogen and 

 carbon in ordinary soil near the surface may be as great, if not greater, than in similar 

 soil in graveyards, e.g. compare samples 10, 14, and 15. 



When, however, we come to compare the amount of organic matter present in the 

 two classes of soil in the deeper strata, we find that the amount of organic nitrogen and 

 carbon in graveyard soil greatly exceeds that present in undisturbed soil, while the 

 proportion of nitrogen to carbon in the polluted soil is higher than in undisturbed soil at 

 a similar level. 



The first nine samples of soil given in the table may be taken as fair samples of 

 ordinary ground which has never been used for agricultural purposes, and therefore may 

 be regarded as virgin soil, while sample 10 may be regarded as a sample of ordinary sur- 

 face soil. Samples 1, 2, 3, and 4 are from a portion of Grange Cemetery which had never 

 been used for burial, was the original soil of the cemetery, and was being trenched to 

 render it more suitable for burial. For the first two feet the ground consisted of a mix- 

 ture of clay and sand, with clay predominating, while below that level it was almost pure 

 sand, with stones here and there. In these samples, it will be noted, the organic matter 

 is small in amount, while the mean relation of nitrogen to carbon is as 1 to 10*25. 

 Samples 5 to 10 (inclusive) are from undisturbed ground in the Arboretum, attached to 

 the Royal Botanic Gardens, and were obtained by means of a boring instrument devised 

 by Dr Hunter Stewart. The ground has, on an average, about 2 feet 6 inches of soil on 

 the surface, below which it is almost pure sand. The amount of organic matter, it will 

 be noted, varies, the mean of the ratio of nitrogen to carbon being 1 to 8 "9. 



The remaining fourteen samples, of which a chemical examination was made, are all 

 from burial-grounds. The amount of organic matter present varies widely, as does also 

 the relation of nitrogen to carbon. 



For convenience of comparison, we may divide the twenty-four samples into two classes, 

 namely " pure soils" and " polluted soils," the term "pure soils" being applied to those 

 which have not been used for interment, and which have not been disturbed in any way, 

 viz., samples 1 to 10 inclusive, while the term "polluted soils" is applied to soils used 

 for burial, whether at a remote or recent date, as well as to lairs, which, although not 

 previously used for interment, must share to a great extent, by drainage through their 

 substance, the pollution arising from the decomposition of bodies buried in adjacent 

 ground. 



