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9
of micro-organisms. As regards the former it may be said that the nearer to the surface the greater
the influence of daily and seasonal changes in temperature ; while as regards the latter examinations
which have been made of soils show that there is considerable difference in the number of bacteria
found in the soil according to the depth from the surface at which it has been obtained. Sternberg,
writing on the subject of bacteria in soil (Text Book of Bacteriology), states as follows—
(39.) "In some experiments made in 1881, Koch ascertained that in soil which had not been
"disturbed but few bacteria were to be found at the depth of a metre, and this fact has since been
"established by the extended researches of Friinkel.
(40.) "Friinkel has given special attention to the examination of undisturbed soil not in the
" immediate vicinity of dwellings.
(41.) "The greatest number was not immediately upon the surface, but at from one-quarter to
"one-half metre below the surface.
(42.) "At a depth of three-quarters of a metre to a metre-and-a-half from the surface there was a
"very great and abrupt diminution in the number of germs.
(43.) "The most important fact developed by Fränkel's researches is that in virgin soil there is a
"dividing line at a depth of from three-quarters to one-and-a-half metres, below which very few
"bacteria are found."
(44.) In the case of ground which has been subject to disturbance, such as the digging of excavations
which are then filled in again by the soil which has been excavated, as is the case in burial places,
it is to be expected that examination of the soil might give different results owing to this cause alone,
while the placing at some depth in it of a body carrying bacteria, as must be the case with a human
corpse, would further tend to cause a difference. In a paper by Dr. J. Buchanan Young, published in
vol. 37 of the Transactions of the Royal Society of Edinburgh, on an examination of soil, at different
depths, it is shown that" the soil of graveyards contains as a rule more bacteria than virgin soil, the
difference "being most marked in the deeper layers, although the number of bacteria is not so great as
"one would expect." Dr. Young refers in his paper to a research by Reimers on soil in churchyards, which
demonstrated the fact, confirmed by his own examinations—that the number of micro-organisms is not
greatest immediately under the coffin, but at a short distance above, although the number in the
vicinity of the coffin was comparatively great, and further, that the number of bacteria diminishes rapidly
in the soil under the coffin. Thus in two experiments the following results were obtained—
(1) In the superficial layers of the soil 320,100 bacteria per c.c.
At a depth within 1.2 metre of the coffin 844,500 ,, ,,
At a depth 1.6 metre just under coffin 142,300 „ „
(2) No coffin found but many bones at a depth of ].5 metre from the surface.
At a depth of 1 metre 985,000 bacteria.
„ „ 1.8 „ 244,600
„ 2 „ 15,600 „
(45.) It is difficult to say to what extent the increase in the number of bacteria in soil at a depth
from the surface is due to bacteria carried by the body itself, but increase caused in this way must
vary considerably according to the condition of the body, the nature of the disease which has proved
fatal and perhaps the time which has elapsed between death and burial. Excluding diseases which
are due to the invasion of the organs and fluids of the body by pathogenic organisms, the internal
tissues of a body are at the time of death free from the presence of bacteria, except in the case of
the alimentary tract. The organisms naturally present in this part of the body as soon as the person
is dead initiate the process of decomposition. By causing softening of the tissues they are gradually
able to spread from within outwards, and so prepare the body for the action of micro-organisms
from without. In all probability the organisms which exist naturally within the human
body are not able completely to effect the whole cycle of decay, and the action of external microbes
is necessary. Brouardel, in one of a series of lectures on "Death and Sudden Death,"
translated by Benham, states that the first phase in the process of decay of all organic matter
depends on the action of aerobic organisms, that is those requiring the presence of oxygen. This
is followed by a second phase, during which the work is carried on by organisms which can act
either in the presence of oxygen or not, and this is followed by the final stage in which anaerobic
organisms, or those which do not require oxygen for their action, complete the process of decay.
(46.) While, therefore, the number of bacteria at a depth from the surface is increased by disturbing
the soil and interring the body in it, this increase is not likely to be so great as to place the
body, so far as the presence of these needful agents is concerned, in a position as favourable for
complete decay as if it were placed nearer the surface, and such evidence as {here is of the results
of superficial as compared with deep burial confirms this opinion.
(47.) (ii.) Character of the coffins in general use.—The use of coffins made of material—usually
elm or oak—which, when placed in the earth, does not tend to be destroyed, is another factor
which plays a part in frustrating the object of burial in earth graves. That this form of coffin does
not decay is shown by the fact that wooden piles driven into the bed of rivers for the purposes of
bridges, last for indefinite periods, and that the old wooden water mains which are at
times excavated in different parts of London are found in a sound state of preservation.
In the case of coffins the same thing applies, and instances are not
wanting where a grave has been reopened down to the last interred coffin for a
second interment after a considerable period, and the coffin found to be as intact as at the
time of its burial. It is only when the coffin is of a character so fragile as to give way to the superincumbent
weight of earth, or where, owing to moisture, the screws have undergone rusting and swelling
and so caused bursting of the wood that opportunity arises for any contact between the corpse and the
surrounding earth. In any case, the use of such coffins is to approximate the conditions of this socalled
earth burial to that of entombment with this difference that the absence of a hermetically-sealed
coffin, such as one of lead, affords opportunity for the gaseous and liquid products of decomposition
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