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Full text of "The formation of vegetable mould, through the action of worms : with observations on their habits"

Presented by 
Dr. Pearl Oliphant 




COLLEGE OP' OSTEOPATH 1C PHYSICIANS 
AND SURGEONS LOS ANGELES, CALIFORNIA ~ 



THE FORMATION 

OF 

VEGETABLE MOULD, 

THROUGH THE 

ACTION OF WOEMS, 

WITH 

OBSERVATIONS ON THEIR HABITS. 



BY CHAELES DAEWIN, LL.D,, F.E.S. 



THIRTEENTH THOUSAND. 



WITH ILLUSTRATIONS. 



LONDON: 
JOHN MUREAY, ALBEMAELE STEEET.. 

1897. 



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CONTENTS. 



INTRODUCTION. .... Pages 1-7 

CHAPTEE I. 

HABITS OF WORMS. 

Nature of the sites inhabited Can live long under 
water Nocturnal Wander about at night Often 
lie close to the mouths of their burrows, and are 
thus destroyed in large numbers by birds Structure 
Do not possess eyes, but can distinguish between 
light and darkness Retreat rapidly when brightly 
illuminated, not by a reflex action Power of atten- 
tion Sensitive to heat and cold Completely deaf 
Sensitive to vibrations and to touch Feeble 
power of smell Taste Mental qualities Nature 
of food Omnivorous Digestion Leaves, before 
being swallowed, moistened with a fluid of the 
nature of the pancreatic secretion Extra-stomachal 
digestion Calciferous glands, structure of Cal- 
careous concretions formed in the anterior pair of 
glands The calcareous matter primarily an excre- 
tion, but secondarily serves to neutralise the acids 
generated during the digestive process . 8-56 



iv CONTENTS. 

CHAPTER II. 

HABITS OF WORMS continued. 

Manner in which worms seize objects Their power of 
suction The instinct of plugging up the mouths of 
their burrows Stones piled over the burrows 
The advantages thus gained Intelligence shown by 
worms in their manner of plugging up their burrows 
Various kinds of leaves and other objects thus 
used Triangles of paper Summary of reasons for 
believing that worms exhibit some intelligence 
Means by which they excavate their burrows, by 
pushing away the earth and swallowing it Earth 
also swallowed for the nutritious matter which it 
contains Depth to which "worms burrow, and the 
construction of their burrows Burrows lined with 
castings, and in the upper part with leaves The 
lowest part paved with little stones or seeds 
Manner in which the castings are ejected The 
collapse of old burrows Distribution of worms 
Tower-like castings in Bengal Gigantic castings 
on the Kilgiri Mountains Castings ejected in all 
countries Pages 57-130 

CHAPTER III. 

TIIK AMOUNT OF FINE EARTH BROUGHT UP BY WORMS 
TO THE SURFACE. 

Rate at which various objects strewed on the surface of 
grass-fields are covered up by the castings of worms 
The burial of a paved path The slow subsidence 
of great stones left on the surface The number of 
worms which live within a given space The 



CONTENTS. v 

weight of earth ejected from a burrow, and from all 
the burrows within a given space The thickness 
of the layer of mould which the castings on a given 
space would form within a given time if uniformly 
spread out The slow rate at which mould can 
increase to a great thickness Conclusion. 

Pages 131-177 

CHAPTEK IV. 

THE PART WHICH WORMS HAVE PLAYED IN THE 
BURIAL OF ANCIENT BUILDINGS. 

The accumulation of rubbish on the sites of great cities 
independent of the action of worms The burial of 
a Eoman villa at Abinger The floors and walls 
penetrated by worms Subsidence of a modern 
pavement The buried pavement at Beaulieu Abbey 
Koman villas at Chedworth and Brad ing The 
remains of the Eoman town at Silchester The 
nature of the debris by which the remains are 
covered The penetration of the tesselated floors 
and walls by worms Subsidence of the floors 
Thickness of the mould The old Eoman city of 
Wroxeter Thickness of the mould Depth of the 
foundations of some of the buildings Conclusion. 

178-231 

CHAPTEE V. 

THE ACTION OF WORMS IN THE DENUDATION OF 
THE LAND. 

Evidence of the amount of denudation which the land 
' has undergone Sub-aerial denudation The deposi- 
tion of dust Vegetable mould, its dark colour and 



CONTEXTS. 

fine texture largely due to the action of worms 
The disintegration of rocks by the humus-acids 
Similar acids apparently generated within the 
bodies of worms The action of these acids facilitated 
by the continued movement of the particles of earth 
A thick bed of mould checks the disintegration 
of the underlying soil and rocks Particles of stone 
worn or triturated in the gizzards of worms 
Swallowed stones serve as millstones The levigated 
state of the castings Fragments of brick in the 
castings over ancient buildings well rounded. The 
triturating power of worms not quite insignificant 
under a geological point of view . Pages 232-261 



CHAPTER VI. 

THE DENUDATION OF THE LAND Continued. 

Denudation aided by recently ejected castings flowing 
down inclined grass-covered surfaces The amount 
of earth which annually flows downwards The 
effect of tropical rain on worm-castings The finest 
particles of earth washed completely away from 
castings The disintegration of dried castings into 
pellets, and their rolling down inclined surfaces 
The formation of little ledges on hill-sides, in part 
due to the accumulation of disintegrated castings 
Castings blown to leeward over level land An 
attempt to estimate the amount thus blown The 
degradation of ancient encampments and tumuli 
The preservation of the crowns and furrows on land 
anciently ploughed The formation and amount of 
mould over the Chalk formation . 262-307 



CONTENTS. vii 

CHAPTER VII. 

CONCLUSION. 

Summary of the part which worms have played iu the 
history of the world Their aid in the disintegra- 
tion of rocks In the denudation of the land In 
the preservation of ancient remains In the pre- 
paration of the soil for the growth of plants 
Mental powers of worms Conclusion. 

Pages 308-316 



LNDEX ....... 317-328 



THE 



FORMATION OF VEGETABLE MOUL1>, 

THROUGH THE ACTION OF WORMS, WITH 
OBSERVATIONS OX THEIR HABITS. 



INTRODUCTION. 

THE share which worms have taken in the 
formation of the layer of vegetahle mould,, 
which covers the whole surface of the land 
in every moderately humid country, is the 
subject of the present volume. This mould 
is generally of a blackish colour and a few 
inches in thickness. In different districts it 
differs but little in appearance, although ' it 
may rest on various subsoils. The uniform* 
fineness of the particles of which it is com- 
posed is one of its chief characteristic features ; 
and this may be well observed in any gravelly 
country, where a recently-ploughed field 

B 



2 INTRODUCTION. 

immediately adjoins one which has long re- 
mained undisturbed for pasture, and where 
the vegetable mould is exposed on the sides 
of a ditch or hole. The subject may appear 
an insignificant one, but we shall see that 
it possesses some interest; and the maxim 
"de minimis non curat lex," does not apply 
to science. Even Elie de Beaumont, who 
generally undervalues small agencies and 
their accumulated effects, remarks : * "La 
" couche tres-mince de la terre ve'getale est un 
" monument d'une haute antiquite', et, par le 
" fait de sa permanence, un objet digne d'oc- 
" cuper le geologue, et capable de lui fournir 
' ; des remarques inte'ressantes." Although 
the superficial layer of vegetable mould as a 
whole no doubt is of the highest antiquity, 
yet in regard to its permanence, we shall here- 
after see reason to believe that its component 
particles are in most cases removed at not a 
very slow rate, and are replaced by others 
due to the disintegration of the underlying 
materials. 

As I was led to keep in my study during 
many months worms in pots filled with earth, 

* ' Lc9ons de Geologic Pratique,' torn. i. 1845, p. 140. 



INTRODUCTION. 3 

I became interested in them, and wished to 
learn how far they acted consciously, and how 
much mental power they displayed. I was 
the more desirous to learn something on this 
head, as few observations of this kind have 
been made, as far as I know, on animals so 
low in the scale of organization and so 
poorly provided with sense-organs, as are 
earth-worms. 

In the year 1837, a short paper was read 
by me before the Greological Society of 
London,* " On the Formation of Mould," in 
which it was shown that small fragments of 
burnt marl, cinders, &c., which had been 
thickly strewed over the surface of several 
meadows, were found after a few years lying 
:at the depth of some inches beneath the turf, 
but still forming a layer. This apparent 
sinking of superficial bodies is due, as 
was first suggested to me by Mr. Wedgwood 
of Maer Hall in Staffordshire, to the large 
quantity of fine earth continually brought 
up to the surface by worms in the form of 
castings. These castings are sooner or later 

* ' Transactions Geolog. Soc.' vol. v. p. 505. Read Novem- 
ber 1, 1837. 

B 2 



4 INTRODUCTION. 

spread out and cover up any object left on 
the surface. I was thus led to conclude that 
all the vegetable mould over the whole coun- 
try has passed many times through, and will 
again pass many times through, the intestinal 
canals of worms. Hence the term "animal 
mould " would be in some respects more 
appropriate than that commonly used of 
'* vegetable mould." 

Ten years after the publication of my paper, 
M. D'Archiac, evidently influenced by the doc- 
trines of Elie de Beaumont, wrote about my 
"singuliere the'orie," and objected that it could 
apply only to "les prairies basses et humides;" 
and that "les terres laboure'es, les bois, les 
prairies e'leve'es, n'apportent aucune preuve 
a 1'appui de cette maniere de voir." * But M. 
D'Archiac must have thus argued from inner 
consciousness and not from observation, for 
worms abound to an extraordinary degree in 
kitchen gardens where the soil is continually 
worked, though in such loose soil they generally 
deposit their castings in any open cavities or 
within their old burrows instead of on the 
surface. Hensen estimates that there are 

* ' Histoire des progrfcs du la Geologic,' torn. i. 1847, p. 221 



INTRODUCTION. 5 

about twice as many worms in gardens as in 
corn-fields.* "With respect to "prairies 
elevees," I do not know how it may be in 
France, but nowhere in England have I seen 
the ground so thickly covered with castings 
as on commons, at a height of several hundred 
feet above the sea. In woods again, if the loose 
leaves in autumn are removed, the whole 
surface will be found strewed with castings. 
Dr. King, the superintendent of the Botanic 
Garden in Calcutta, to whose kindness I am 
indebted for many observations on earth- 
worms, informs me that he found, near Nancy 
in France, the bottom of the State forests 
covered over many acres with a spongy layer, 
composed of dead leaves and innumerable 
worm-castings. He there heard the Professor 
of " Amenagement des Forets " lecturing to 
his pupils, and pointing out this case as a 
" beautiful example of the natural cultiva- 
*' tion of the soil ; for year after year the 
<; thrown-up castings cover the dead leaves ; 
"the result being a rich huznus of great 
" thickness." 

* 'Zeitschrift fiir wissenschaft. Zoologie,' B. xxviii. 1877, 
p. 361. 



INTRODUCTION. 

In the year 1869, Mr. Fish* rejected my 
conclusions with respect to the part which 
worms have played in the formation of veget- 
ahle mould, merely on account of their assumed 
incapacity to do so much work. He remarks 
that "considering their weakness and their 
" size, the work they are represented to 
" have accomplished is stupendous." Here we 
have an instance of that inability to sum 
up the effects of a continually recurrent 
cause, which has often retarded the progress 
of science, as formerly in the case of geology, 
and more recently in that of the principle 
of evolution. 

Although these several objections seemed 
to me to have no weight, yet I resolved to 
make more observations of the same kind as 
those published, and to attack the problem on 
another side ; namely, to weigh all the cast- 
ings thrown up within a given time in a 
measured space, instead of ascertaining the 
rate at which objects left on the surface were 
buried by worms. But some of my ob- 
servations have been rendered almost super- 
fluous by an admirable paper by Hensc:i r 

* ' Gardeners' Chronicle,' April 17, 18G9, p. 418. 



INTRODUCTION. 7 

already alluded to, which appeared in 1877.* 
Before entering on details with respect to the 
castings, it will be advisable to give some 
account of the habits of worms from my 
own observations and from those of other 
naturalists. 

* Mr. Darwin's attention was called by Professor Hensen to 
P. E. Miiller's work on Humus in ' Tidsskrift for Skovbrug,' 
Band iii. Heft 1 and 2, Copenhagen, 1878. He had, however, 
no opportunity of consulting Miiller's work. Dr. Miiller pub- 
lished a second paper in 1884 in the same periodical a Danish 
journal of forestry. His results have also been published in 
German, in a volume entitled ' Studien iiber die nattirlichen 
Humusformen, unter deren Einwirkung auf Vegetation und 
Boden,' 8vo., Berlin, 1887. 

[FIRST EDITION, 

October 10th, 1881.] 



HABITS OF WORMS. CHAP. I. 



CHAPTER I. 

HABITS OF WORMS. 

Nature of the sites inhabited Can live long under water- 
Nocturnal Wander about at night Often lie close to the 
mouths of their burrows, and are thus destroyed in large 
numbers by birds Structure Do not possess eyes, but can 
distinguish between light and darkness Retreat rapidly when 
brightly illuminated, not by a reflex action Power of attention 
Sensitive to heat and cold Completely deaf Sensitive to 
vibrations and to touch Feeble power of smell Taste 
Mental qualities Nature of food Omnivorous Digestion 
Leaves before being swallowed, moistened with a fluid of the 
nature of the pancreatic secretion Extra-stomachal digestion 
Calciferous glands, structure of Calcareous concretions 
formed in the anterior pair of glands The calcareous matter 
primarily an excretion, but secondarily serves to neutralise the 
acids generated during the digestive process. 

EARTH-WORMS are distributed throughout the 
world under the form of a few genera, which 
externally are closely similar to one another. 
The British species of Lumbricus have never 
been carefully monographed; but we may 
judge of their probable number from those 
inhabiting neighbouring countries. In Scan- 
dinavia there are eight species, according to 



CHAP. I. SITES INHABITED. 9 

Eisen ;* but two of these rarely burrow in the 
ground, and one inhabits very wet places or 
even lives under the water. We are here 
concerned only with the kinds which bring 
up earth to the surface in the form of cast- 
ings. Hoffmeister says that the species in 
Germany are not well known, but gives the 
same number as Eisen, together with some 
strongly marked varieties.f 

Earth-worms abound in England in many 
different stations. Their castings may be 
seen in extraordinary numbers on commons 
and chalk-downs, so as almost to cover the 
whole surface, where the soil is poor and the 
grass short and thin. But they are almost or 
quite as numerous in some of the London 
parks, where the grass grows well and the 
soil appears rich. Even on the same field 
worms are much more frequent in some places 
than in others, without any visible difference 
in the nature of the soil. They abound in 
paved court-yards close to houses ; and an 
instance will be given in which they had 

* ' Bidrag till Skandinaviens Oligoclifetfauna,' 1871. 
t ' Die bis jetzt bekannten Arten aus der Familie der Begen- 
\viirmcr,' 1845. 



10 HABITS OF AVOIUIS. CHAP. I. 

burrowed through the floor of a very damp 
cellar. I have seen worms in black peat in a 
boggy field ; but they are extremely rare, or 
quite absent in the drier, brown, fibrous peat, 
which is so much valued by gardeners. On 
dry, sandy or gravelly tracks, where heath 
with some gorse, ferns, coarse grass, moss and 
lichens alone grow, hardly any worms can 
be found. But in many parts of England, 
wherever a path crosses a heath, its surface 
becomes covered with a fine short sward. 
Whether this change of vegetation is due to 
the taller plants being killed by the occasional 
trampling of man and animals, or to the soil 
being occasionally manured by the droppings 
from animals, I do not know.* On such 
grassy paths worm-castings may often be seen. 
On a heath in Surrey, which was carefully 
examined, there were only a few castings on 
these paths, where they were much inclined ; 

* There is even some reason to believe that pressure is actually 
favourable to the growth of grasses, for Professor Buckman, who 
made many observations on their growth in the experimental, 
gardens of the Royal Agricultural College, remarks (' Gardeners' 
Chronicle,' 1854, p. 619) : " Another circumstance in the cultiva- 
tion of grasses in the separate form or small patches, is the 
impossibility of rolling or treading them firmly, without which 
no pasture can continue good." 



CHAP. I. SITES INHABITED. II 

but on the more level parts, where a bed of 
fine earth had been washed down from the 
steeper parts and had accumulated to a thick- 
ness of a few inches, worm-castings abounded. 
These spots seemed to be overstocked with 
worms, so that they had been compelled to 
spread to a distance of a few feet from the 
grassy paths, and here their castings had been 
thrown up among the heath ; but beyond this 
limit, not a single casting could be found. A 
layer, though a thin one, of fine earth, which 
probably long retains some moisture, is in 
all cases, as I believe, necessary for their 
existence ; and the mere compression of the 
soil appears to be in some degree favourable 
to them, for they often abound in old gravel 
walks, and in foot-paths across fields. 

Beneath large trees few castings can be 
found during certain seasons of the year, and 
this is apparently due to the moisture having 
been sucked out of the ground by the innu- 
merable roots of the trees ; for such places 
may be seen covered with castings after the 
heavy autumnal rains. Although most cop- 
pices and woods support many worms, yet in a 
forest of tall and ancient beech-trees in Knole 



12 HABITS OF WOEMS. CHAP. I. 

Park, where the ground beneath was bare of 
all vegetation, not a single casting could be 
found over wide spaces, even during the 
autumn. Nevertheless, castings were abun- 
dant on some grass-covered glades and in- 
dentations which penetrated this forest. On 
the mountains of North Wales and on the 
Alps, worms, as I have been informed, are in 
most places rare ; and this may perhaps be 
due to the close proximity of the sub- 
jacent rocks, into which worms cannot 
burrow during the winter so as to escape 
being frozen. Dr. Mclntosh, however, found 
worm-castings at a height of 1500 feet on 
Schiehallion in Scotland. They are numerous 
on some hills near Turin at from 2000 to 
3000 feet above the sea, and at a great 
altitude on the Nilgiri Mountains in South 
India and on the Himalaya 

Earth-worms must be considered as terres- 
trial animals, though they are still in one 
sense semi-aquatic, like the other members of 
the great class of annelids to which they 
belong. M. Perrier found that their ex- 
posure to the dry air of a room for only a 
single night was fatal to them. On the 



CHAP. I. NOCTUKNAL. 13 

other hand he kept several large worms alive 
for nearly four months, completely submerged 
in water.* During the summer when the 
ground is dry, they penetrate to a consider- 
able depth and cease to work, as they do 
during the winter when the ground is frozen. 
Worms are nocturnal in their habits, and at 
night may be seen crawling about in large 
numbers, but usually with their tails still 
inserted in their burrows. By the expansion 
of this part of their bodies, and with the help 
of the short, slightly reflexed bristles, with 
which their bodies are armed, they hold 
so fast that they can seldom be dragged 
out of the ground without being torn into 
pieces.f During the day they remain in 
their burrows, except at the pairing season, 
when those which inhabit adjoining burrows 
expose the greater part of their bodies for 
an hour or two in the early morning. Sick 

* I shall have occasion often to refer to M. Perrier's admirable 
memoir, ' Organisation des Lombriciens terrestres ' in ' Archives 
de Zoolog. expe'r.' torn. iii. 1874, p. 372. C. F. Morren (' De 
Luinbrici terrestris Hist. Nat.' 1829, p. 14) found that worms 
endured immersion for fifteen to twenty days in summer, but 
that in winter they died when thus treated. 

t Morren, 'De Lumbrici terrestris Hist. Nat.' &c., 1829, 
p. 67. 



14 HABITS OF WORMS. CHAP. I. 

individuals, which are generally affected by 
the parasitic larvae of a fly, must also be ex- 
cepted, as they wander about during the day 
and die on the surface. After heavy rain 
succeeding dry weather, an astonishing num- 
ber of dead worms may sometimes be seen 
lying on the ground. Mr. Galton informs 
me that on one such occasion (March, 1881), 
the dead worms averaged one for every 
two and a half paces in length on a walk in 
Hyde Park, four paces in width. He counted 
no less than 45 dead worms in one place in 
a length of sixteen paces. From the facts 
above given, it is not probable that these 
worms could have been drowned, and if they 
had been drowned they would have perished 
in their burrows. I believe that they were 
already sick, and that their deaths were 
merely hastened by the ground being flooded. 
It has often been said that under ordinary 
circumstances healthy worms never, or very 
rarely, completely leave their burrows at 
night ; but this is an error, as White of Sel- 
borne long ago knew. In the morning, after 
there has been heavy rain, the film of mud 
or of very fine sand over gravel-walks is often 



CHAP. I. WANDER FROM THEIR BURROWS. 15 

plainly marked with their tracks. I have 
noticed this from August to May, both months 
included, and it probably occurs during the 
two remaining months of the year when 
they are wet. On these occasions, very few 
dead worms could anywhere be seen. On 
January 31, 1881, after a long-continued 
and unusually severe frost with much snow, 
as soon as a thaw set in, the walks were 
marked with innumerable tracks. On one 
occasion, five tracks were counted crossing 
a space of only an inch square. They could 
sometimes be traced either to or from the 
mouths of the burrows in the gravel-walks, 
for distances between 2 or 3 up to 15 yards. 
I have never seen two tracks leading to the 
same burrow ; nor is it likel}~, from what we 
shall presently see of their sense-organs, that 
a worm could find its way back to its burrow 
after having once left it. They apparently 
leave their burrows on a voyage of discovery, 
and thus they find new sites to inhabit. 

Morren states * that worms often lie for 
hours almost motionless close beneath the 
mouths of their burrows. I have occasionally 
noticed the same fact with worms kept in 

* ' De Lumbrici terrestris Hist. Nat.' &c., p. 14. 



16 HABITS OF WORMS. CHAP. I. 

pots in the house ; so that hy looking down 
into their burrows, their heads could just be 
seen. If the ejected earth or rubbish over 
the burrows be suddenly removed, the end 
of the worm's body may very often be seen 
rapidly retreating. This habit of lying near 
the surface leads to their destruction to an 
immense extent. Every morning during cer- 
tain seasons of the year, the thrushes and 
blackbirds on all the lawns throughout the 
country draw out of their holes an astonishing 
number of worms ; and this they could not 
do, unless they lay close to the surface. It 
is not probable that worms behave in this 
manner for the sake of breathing fresh air, 
for we have seen that they can live for a 
long time under water. I believe that they lie 
near the surface for the sake of warmth, es- 
pecially in the morning ; and we shall here- 
after find that they often coat the mouths 
of their burrows with leaves, apparently to 
prevent their bodies from coming into close 
contact with the cold damp earth. It is said 
that they completely close their burrows 
during the winter. 

Structure. A few remarks must be made 
on this subject. The body of a large worm 



CHAP. I. THEIR STRUCTURE. 17 

consists of from 100 to 200 almost cylindrical 
rings or segments, each furnished with minute 
bristles. The muscular system is well 
developed. Worms can crawl backwards as 
well as forwards, and by the aid of their 
affixed tails can retreat with extraordinary 
rapidity into their burrows. The mouth is 
situated at the anterior end of the body, and 
is provided with a little projection (lobe or lip, 
as it has been variously called) which is used 
for prehension. Internally, behind the mouth, 
there is a strong pharynx, shown in the ac- 
.companying diagram (Fig. 1) which is pushed 
forwards when the animal eats, and this part 
corresponds, according to Perrier, with the pro- 
trudable trunk or proboscis of other annelids. 
The pharynx leads into the oesophagus, on 
each side of which in the lower part there 
are three pairs of large glands, which secrete 
a surprising amount of carbonate of lime. 
These calciferous glands are highly remark- 
able, for nothing like them is known in any 
other animal. Their use will be discussed 
when we treat of the digestive process. In 
most of the species, the oesophagus is enlarged 
into a crop in front of the gizzard. This 

c 



18 



HABITS OF WORMS. 



CHAP. I. 



latter organ is lined with a smooth thick 
chitinous membrane, and 
is surrounded by weak 
longitudinal, but power- 
ful transverse muscles. 
Perrier saw these muscles 
in energetic action; and, as 
he remarks, the trituratioii 
of the food must be chiefly 
effected by this organ, for 
worms possess no jaws or 
teeth of any kind. Grains 
of sand and small stones, 
from the -^ to a little 
more than the -^ inch in 
diameter, may generally 
be found in their gizzards 
and intestines. As it is 
certain that worms swal- 
low many little stones, in- 

Diogmmrf the alimen- dependency of those swal- 
lowed while excavating 
burrows, it is prob- 



Mout'a. 



Pharynx. 



(Esophagus. 



Calc'ferous glands. 



(Esophagus. 



Crop. 



Upper part of in- 
testine. 



tary canal of an earth- 
worm (Lumbricus), 
copied from 1'ay Lan- 

kcster in 'Quart, able that they serve, like 
m iii_ st ones, to triturate 

. ' 

their food. The gizzard 
opens into the intestine, 



Journ. of Microscop. 
Sc.' vol. xv. N.S. 
pi. vii. 



CHAP. I. THEIK SENSES. 19 

which runs in a straight course to the vent 
at the posterior end of the body. The intes- 
tine presents a remarkable structure, the 
typhlosolis, or, as the old anatomists called 
it, an intestine within an intestine ; and Cla- 
parede * has shown that this consists of a 
deep longitudinal involution of the walls of 
the intestine, by which means an extensive 
absorbent surface is gained. 

The circulatory system is well developed. 
"Worms breathe by their skin, as they do not 
possess any special respiratory organs. The 
two sexes are united in the same individual, but 
two individuals pair together. The nervous 
system is fairly well developed ; and the two 
almost confluent cerebral ganglia are situated 
very near to the anterior end of the body. 

Senses. Worms are destitute of eyes, and 
at first I thought that they were quite in- 
sensible to light ; for those kept in confine- 
ment were repeatedly observed by the aid of 
a candle, and others out of doorS by the aid 
of a lantern, yet they were rarely alarmed, 
although extremely timid animals. Other 

* Histolog. Untersuchungen iiber die Regenwiirmer. 'Zeit- 
scbrift fur wissenschaft. Zoologie,' B. six., 1869, p. 611. 

c 2 



20 HABITS OF WORMS. CHAP. I. 

persons have found no difficulty in observing 
worms at night by the sanie means.* 

Hoffmeister, however, states f that worms, 
with the exception of a few individuals, are 
extremely sensitive to light ; but he admits 
that in most cases a certain time is requisite 
for its action. These statements led me to 
watch on many successive nights worms kept 
in pots, which were protected from currents 
of air by means of glass plates. The pots 
were approached very gently, in order that 
no vibration of the floor should be caused. 
When under these circumstances worms were 
illuminated by a bull's-eye lantern having 
slides of dark red and blue glass, which in- 
tercepted so much light that they could be seen 
only with some difficulty, they were not at all 
affected by this amount of light, however long 
they were exposed to it. The light, as far 
as I could judge, was brighter than that from 
the. full moon. Its colour apparently made 
no difference* in the result. When they were 

* For, instance, Mr. Bridgman and Mr. Newman ('The 
Zoologist,' vol. vii. 1849, p. 2576), and some friends who observed 
worms for me. 

f ' Familie der Regenwiirmer.' 1845, p. 18. 



CHAP. I. THEIR SENSES. 21" 

illuminated by a candle, or even by a bright 
paraffin lamp, they were not usually affected 
at first. Nor were they when the light was- 
alternately admitted and shut off. Some- 
times, however, they behaved very differ- 
ently, for as soon as the light fell on them, 
they withdrew into their burrows with 
almost instantaneous rapidity. This occurred 
perhaps once out of a dozen times. When 
they did not withdraw instantly, they often 
raised the anterior tapering ends of their 
bodies from the ground, as if their attention- 
was aroused or as if surprise was felt ; or 
they moved their bodies from side to side as- 
if feeling for some object. They appeared 
distressed by the light ; but I doubt whether 
this was really the case, for on two occasions 
after withdrawing slowly, they remained for 
a long time with their anterior extremities 
protruding a little from the mouths of their 
burrows, in which position they were ready 
for instant and complete withdrawal. 

"When the light from a candle was con- 
centrated by means of a large lens on the 
anterior extremity, they generally withdrew 
instantly ; but this concentrated light failed 



22 HABITS OF WORMS. CHAP. T. 

to act perhaps once out of half a dozen trials. 
The light was on one occasion concentrated 
6>n a worm lying beneatli water in a saucer, 
and it instantly withdrew into its burrow. 
In all cases the duration of the light, unless 
extremely feeble, made a great difference in 
the result; for worms left exposed before a 
paraffin lamp or a candle invariably retreated 
into their burrows within from five to fifteen 
minutes ; and if in the evening the pots were 
illuminated before the worms had come out of 
their burrows, they failed to appear. 

From the foregoing facts it is evident that 
light affects worms by its intensity and by 
its duration. It is only the anterior 
extremity of the body, where the cerebral 
ganglia lie, which is affected by light, as 
Hoffmeister asserts, and as I observed on 
many occasions. If this part is shaded, other 
parts of the body may be fully illuminated, 
and no effect will be produced. As these 
animals have no eyes, we must suppose that 
the light passes through their skins, and in 
some manner excites their cerebral ganglia. 
It appeared at first probable that the dif- 
ferent manner in which they were affected on 



<JIIAP. I. THEIR SENSES. 23 

different occasions might be explained, either 
by the degree of extension of their skin and 
its consequent transparency, or by some 
particular incidence of the light ; but I 
could discover no such relation. One thing 
was manifest, namely, that when worms were 
employed in dragging leaves into their 
burrows or in eating them, and even during 
the short intervals whilst they rested from 
their work, they either did not perceive 
the light or were regardless of it ; and this 
occurred even when the light was concentrated 
on them through a large lens. So, again, 
whilst they are paired, they will remain for 
an hour or two out of their burrows, fully 
exposed to the morning light ; but it appears 
from what Hoffmeister says that a light 
will occasionally cause paired individuals to 
separate. 

When a worm is suddenly illuminated and 
dashes like a rabbit into its burrow to use 
the expression employed by a friend we are 
at first led to look at the action as a reflex one. 
The irritation of the cerebral ganglia appears 
to cause certain muscles to contract in an 
inevitable manner, independently of the will 



24 HABITS OF WORMS. CHAP. I. 

or consciousness of the animal, as if it were 
an automaton. But the different effect 
which a light produced 011 different occasions, 
and especially the fact that a worm when in 
any way employed and in the intervals of 
such employment, whatever set of muscles 
and ganglia may then have been brought into 
play, is often regardless of light, are opposed 
to the view of the sudden withdrawal being 
a simple reflex action. With the higher 
animals, when close attention to some object 
leads to the disregard of the impressions 
which other objects must be producing on 
them, we attribute this to their attention 
being then absorbed ; and attention implies 
the presence of a mind. Every sportsman 
knows that he can approach animals whilst 
they are grazing, fighting or courting, much 
more easily than at other times. The state, 
also, of the nervous system of the higher 
animals differs much at different times, for 
instance, a horse is much more readily startled 
at one time than at another. The comparison 
here implied between the actions of one ot 
the higher animals and of one so low in the 
scale as an earth-worm, may appear far- 



CHAP. I. THEIR SENSES. 25 

fetched ; for we thus attribute to the worm 
attention and some mental power, neverthe- 
less I can see no reason to doubt the justice 
of the comparison. 

Although worms cannot be said to possess 
the power of vision, their sensitiveness to 
light enables them to distinguish between 
day and night ; and they thus escape extreme 
danger from the many diurnal animals which 
prey on them. Their withdrawal into their 
burrows during the day appears, however, 
to have become an habitual action; for 
worms kept in pots covered by glass-plates, 
over which sheets of black paper were 
spread, and placed before a north-east win- 
dow, remained during the day-time in their 
burrows and came out every night ; and they 
continued thus to act for a week. No doubt 
a little light may have entered between the 
sheets of glass and the blackened paper ; 
but we know from the trials with coloured 
glass, that worms are indifferent to a small 
amount of light. 

Worms appear to be less sensitive to 
moderate radiant heat than to a bright light. 
I judge of this from having held at different 



26 HABITS OP TVOKMS. CHAP. I, 

times a poker heated to dull redness near 
some worms, at a distance which caused a 
very sensible degree of warmth in my hand. 
One of them took no notice ; a second with- 
drew into its burrow, but not quickly ; the 
third and fourth much more quickly, and the 
fifth as quickly as possible. The light from 
a candle, concentrated by a lens and passing- 
through a sheet of glass which would intercept 
most of the heat-rays, generally caused a 
much more rapid retreat than did the heated 
poker. Worms are sensitive to a low temper- 
ature, as may be inferred ' from their not 
coming out of their burrows during a frost. 

Worms do not possess any sense of hearing. 
They took not the least notice of the shrill 
notes from a metal whistle, which was re- 
peatedly sounded near them ; nor did they 
of the deepest and loudest tones of a bassoon. 
They were indifferent to shouts, if care was 
taken that the breath did not strike them. 
When placed on a table close to the keys of 
a piano, which was played as loudly as 
possible, they remained perfectly quiet. 

Although they are indifferent to undula- 
tions in the air audible by us, they are 



CHAP. I. THEIR SENSES. 27 

extremely sensitive to vibrations in any solid 
object. When the pots containing two 
worms which had remained quite indifferent 
to the sound of the piano, were placed on 
this instrument, and the note C in the bass 
elef was struck, both instantly retreated into 
their burrows. After a time they emerged, 
and when Gr above the line in the treble clef 
was struck they again retreated. Under 
similar circumstances on another night one 
worm dashed into its burrow on a very high 
note being struck only once, and the other 
worm when C in the treble clef was struck. 
On these occasions the worms were not 
touching the sides of the pots, which stood 
in saucers ; so that the vibrations, before 
reaching their bodies, had to pass from the 
sounding board of the piano, through the 
saucer, the bottom of the pot and the damp, 
not very compact earth on which they lay 
with their tails in their burrows. They 
often showed their sensitiveness when the 
pot in which they lived, or the table on 
which the pot stood, was accidentally and 
lightly struck; but they appeared less sensi- 
tive to such jars than to the vibrations of the 



28 HABITS OF WORMS. CHAP. I. 

piano ; and their sensitiveness to jars varied 
much at different times. 

It has often been said that if the ground is 
beaten or otherwise made to tremble, worms 
believe that they are pursued by a mole 
and leave their burrows. From one account 
that I have received, I have no doubt that 
this is often the case; but a gentleman 
informs me that he lately saw eight or ten 
worms leave their burrows and crawl about 
the grass on some boggy land on which two 
men had just trampled while setting a trap ; 
and this occurred in a part of Ireland where 
there were no moles. I have been assured 
by a Volunteer that he has often seen many 
large earth-worms crawling quickly about 
the grass, a few minutes after his company 
had fired a volley with blank cartridges. The 
Peewit (Tringavanellus, Linn.) seems to know 
instinctively that worms will emerge if the 
ground is made to tremble ; for Bishop 
Stanley states (as I hear from Mr. Moorhouse) 
that a young peewit kept in confinement used 
to stand on one leg and beat the turf with 
the other leg until the worms crawled out 
of their burrows, when they were instantly 



CHAP. I. THEIR SENSES. 29 

devoured. Nevertheless, worms do not in- 
variably leave their burrows when the ground 
is mcide to tremble, as I know by having 
beaten it .with a spade, but perhaps it was 
beaten too violently. 

The whole body of a worm is sensitive to 
contact. A slight puff of air from the mouth 
causes an instant retreat. The glass plates 
placed over the pots did not fit closely, and 
blowing through the very narrow chinks thus 
left, often sufficed to cause a rapid retreat. 
They sometimes perceived the eddies in the 
air caused by quickly removing the glass 
plates. When a worm first comes out of its 
burrow, it generally moves the much ex- 
tended anterior extremity of its body from 
side to side in all directions, apparently as an 
organ of touch ; and there is some reason to 
believe, as we shall see in the next chapter, 
that they are thus enabled to gain a general 
notion of the form of an object. Of all their 
senses that of touch, including in this term 
the perception of a vibration, seems much the 
most highly developed. 

In worms the sense of smell apparently is 
confined to 'the. perception, of certain odours, 



30 HABITS OF WORMS. CHAP. I. 

and is feeble. They were quite indifferent to 
my breath, as long" as I breathed on them very 
gently. This was tried, because it appeared 
possible that they might thus be warned of 
the approach of an enemy. They exhibited, 
the same indifference to my breath whilst I 
chewed some tobacco, and while a pellet of 
cotton-wool with a few drops of millefleurs 
perfume or of acetic acid was kept in my 
mouth. Pellets of cotton-wool soaked in 
tobacco juice, in millefleurs perfume, and in 
paraffin, were held with pincers and were 
waved about within two or three inches of 
several worms, but they took no notice. On 
one or two occasions, however, when acetic 
acid had been placed on the pellets, the worms 
appeared a little uneasy, and this was 
probably due to the irritation of their skins. 
The perception of such unnatural odours 
would be of no service to worms ; and as such 
timid creatures would almost certainly exhibit 
some signs of any new impression, we may 
conclude that they did not perceive these 
odours. 

The result was different when cabbage- 
leaves and pieces of onion were employed, 



CHAP. I. THEIR SENSES. 31 

both of which are devoured with much relish 
by worms. Small square pieces of fresh and 
half-decayed cabbage-leaves and of onion 
bulbs were on nine occasions buried in my 
pots, beneath about i of an inch of common 
garden soil ; and they were always discovered 
by the worms. One bit of cabbage was dis- 
covered and removed in the course of two 
hours ; three were removed by the next 
morning, that is, after a single night ; two 
others after two nights ; and the seventh bit 
after three nights. Two pieces of onion were 
discovered and removed after three nights. 
Bits of fresh raw meat, of which worms are 
very fond, were buried, and were not dis- 
covered within forty-eight hours, during 
which time they had not become putrid. The 
earth above the various buried objects was 
generally pressed down only slightly, so as 
not to prevent the emission of any odour. 
On two occasions, however, the surface was 
well watered, and was thus rendered some- 
what compact. After the bits of cabbage and 
onion had been removed, I looked beneath 
them to see whether the worms had acci- 
dentally come up from below, but there was- 



32 HABITS OF WOBMS. CHAP. I. 

no sign of a burrow; and twice the buried 
objects were laid on pieces of tin-foil which 
were not in the least displaced. It is of 
course possible that the worms whilst moving 
about on the surface of the ground, with their 
tails affixed within their burrows, may have 
poked their heads into the places where the 
above objects were buried ; but I have never 
seen worms acting in this manner. Some 
pieces of cabbage-leaf and of onion were twice 
buried beneath very fine ferruginous sand, 
w.hich was slightly pressed down and well 
watered, so as to be rendered very compact, 
and these pieces were never discovered. On 
a third occasion the same kind of sand was 
neither pressed down nor watered, <ind the 
pieces of cabbage were discovered and re- 
moved after the second night. These several 
facts indicate that worms possess some power 
of smell ; and that they discover by this 
means odoriferous and much-coveted kinds 
of food. 

It may be presumed that all animals which 
feed on various substances possess the sense 
of taste, and this is certainly the case with 
worms. Cabbage-leaves are much liked by 



CHAP. I. THEIB SENSES. 33- 

worms; and it appears that they can dis- 
tinguish between different varieties ; but this- 
may perhaps be owing to differences in their 
texture. On eleven occasions pieces of the> 
fresh leaves of a common green variety and 
of the red variety used for pickling were 
given them, and they preferred the green, 
the red being either wholly neglected or much 
less gnawed. On two other occasions, how- 
ever, they seemed to prefer the red. Half- 
decayed leaves of the red variety and fresh 
leaves of the green were attacked about 
equally. When leaves of the cabbage, horse- 
radish (a favourite food) and of the onion were- 
given together, the latter were always and 
manifestly preferred. Leaves of the cab- 
bage, lime-tree, Ampelopsis, parsnip (Pasti- 
naca), and celery (Apium) were likewise 
given together; and those of the celery 
were first eaten. But when leaves of cab- 
oage, turnip, beet, celery, wild cherry and 
carrots were given together, the two lattef 
kinds, especially those of the carrot, were- 
preferred to all the others, including those 
of celery. It was also manifest after many 
trials that wild cherry leaves were greatly 

D 



34 HABITS OP WORMS. CHAP. I. 

preferred to those of the lime-tree and hazel 
(Corylus). According to Mr. Bridgman the 
half-decayed leaves of Phlox verna are par- 
ticularly liked by worms.* 

Pieces of the leaves of cabbage, turnip, 
horse-radish and onion were left on the pots 
during 22 days, and were all attacked and 
had to be renewed; but during the whole 
of this time leaves of an Artemisia and of 
the culinary sage, thyme and mint, mingled 
with the above leaves, were quite neglected 
excepting those of the mint, which were occa- 
sionally and very slightly nibbled. These 
latter four kinds of leaves do not differ in 
texture in a manner which could make them 
disagreeable to worms; they all have a 
strong taste, but so have the four first men- 
tioned kinds of leaves ; and the wide differ- 
ence in the result must be attributed to a 
preference by the worms for one taste over 
another. 

Mental Qualities. There is little to be said 
on this head. We have seen that worms are 
timid. It may be doubted whether they 
suffer as much pain when injured, as they 

* The Zoologist,' vol. vii. 1849, p. 2576. 



CHAP. I. MENTAL QUALITIES. 35 

seem to express by their contortions. Judging 
by their eagerness for certain kinds of food, 
they must enjoy the pleasure of eating. 
Their sexual passion is strong enough to 
overcome for a time their dread of light. 
'They perhaps have a trace of social feeling, 
for they are not disturbed by crawling over 
each other's bodies, and they sometimes lie 
in contact. According to Hoffmeister they 
pass the winter either singly or rolled up 
with others into a ball at the bottom of their 
burrows.* Although worms are so remark- 
ably deficient in the several sense-organs, 
this does not necessarily preclude intelligence, 
as we know from such cases as those of Laura 
Bridgman; and we have seen that when their 
attention is engaged, they neglect impressions 
to which they would otherwise have attended ; 
and attention indicates the presence of a mind 
of some kind. They are also much more 
easily excited at certain times than at others. 
They perform a few actions instinctively, that 

* * Familie der Eegenwiirmer,' p. 13. Dr. Sturtevant states 
in the ' New York Weekly Tribune ' (May 19, 1880) that he kept 
three worms in a pot, which was allowed to become extremely 
dry ; and these worms were found " all entwined together, 
forming a round mass and in good condition." 

D 2 



36 HABITS OF WORMS. CHAP. L 

is, all the individuals, including the young, 
perform such actions in nearly the same 
fashion. This is shown by the manner in 
which the species of Pericha3ta eject their 
castings, so as to construct towers; also by 
the manner in which the burrows of the 
common earth-worm are smoothly lined with 
fine earth and often with little stones, and 
the mouths of their burrows with leaves. 
One of their strongest instincts is the plug- 
ging up the mouths of their barrows with 
various objects ; and very young worms act 
in this manner. But some degree of in- 
telligence appears, as we shall see in the next 
chapter, to be exhibited in this work, a 
result which has surprised me more than, 
anything else in regard to worms. 

Food and Digestion. Worms are omnivo- 
rous. They swallow an enormous quantity of 
earth, out of which they extract any diges- 
tible matter which it may contain ; but to 
this subject I must recur. They also con- 
sume a large number of half-decayed leaves 
of all kinds, excepting a few which have an 
unpleasant taste or are too tough for them ;. 
likewise petioles, peduncles, and decayed 



CHAP. I. FOOD AND DIGESTION. 37 

flowers. But they will also consume fresh 
leaves, as I have found by repeated trials. 
According to Morren * they will eat particles 
of sugar and liquorice ; and the worms which 
I kept drew many bits of dry starch into 
their burrows, and a large bit had its angles 
well rounded by the fluid poured out of their 
mouths. But as they often drag particles of 
soft stone, such as of chalk, into their burrows, 
I feel some doubt whether the starch was 
used as food. Pieces of raw and roasted meat 
were fixed several times by long pins to the 
surface of the soil in my pots, and night after 
night the worms could be seen tugging at 
them, with the edges of the pieces engulfed 
in their mouths, so that much was consumed. 
Raw fat seems to be preferred even to raw 
meat or to any other substance which was 
given them, and much was consumed. They 
are cannibals, for the two halves of a dead 
worm placed in two of the pots were dragged 
into the burrows and gnawed ; but as far as 
I could judge, they prefer fresh to putrid 
meat, and in so far I differ from Hoffmeister. 

* ' DC Lumbrici terrestris Hist. Nat,' p. 19. 



38 HABITS OF WORMS. CHAI>. I. 

Leon Fredericq states* that the digestive 
fluid of worms is of the same nature as the 
pancreatic secretion of the higher animals ;. 
and this conclusion agrees perfectly with the 
kinds of food which worms consume. Pan- 
creatic juice emulsifies fat, arid we have just 
seen how greedily worms devour fat ; it 
dissolves fibrin, and worms eat raw meat ; it 
converts starch into grape-sugar with wonder- 
ful rapidity, and we shall presently show that 
the digestive fluid of worms acts on starch. f 
But they live chiefly on half-decayed leaves ; 
and these would be useless to them unless they 
could digest the cellulose forming the cell- 
walls ; for it is well known that all other nutri- 
tious substances are almost completely with- 
drawn from leaves, shortly before they fall 
off. It has, however, now been ascertained 
that some forms of cellulose, though very 
little or not at all attacked by the gastric 

* Archives de Zoologie expe'rimentale,' torn. vii. 1878, p. 394. 
When I wrote the above passage, I was not aware that Kruken- 
berg (' Untersuchungen a. d. physiol. Inst. d. Univ. Heidelberg,' 
Bd. ii. p. 37, 1877) had previously investigated the digestive 
juice of Lumbricus. He states that it contains a peptic, and, 
diastatic, as well as a tryptic ferment. 

t On the action of the pancreatic ferment, see ' A Text-Book 
of Physiology/ by Michael Foster, 2nd edit. pp. 198-203. 1878. 



CHAP. I. FOOD AND DIGESTION. 39 

secretion of the higher animals, are acted on 
by that from the pancreas.* 

The half-decayed or fresh leaves which 
worms intend to devour, are dragged into the 
mouths of their burrows to a depth of from 
cne to three inches, and are then moistened 
with a secreted fluid. It has been assumed 
that this fluid serves to hasten their decay ; 
but a large number of leaves were twice 
pulled out of the burrows of worms and kept 
for many weeks in a very moist atmosphere 
under a bell-glass in my study ; and the parts 
which had been moistened by the worms did 
not decay more quickly in any plain manner 
than the other parts. When fresh leaves 
were given in the evening to worms kept in 
confinement and examined early on the next 
morning, therefore not many hours after they 
had been dragged into the burrows, the fluid 
with which they were moistened, when tested 
with neutral litmus paper, showed an alkaline 
reaction. This was repeatedly found to be 
the case with celery, cabbage and turnip 
leaves. Parts of the same leaves which had 



* Schmulewitsch, ' Action des Sues digestifs sur la Cellulose.' 
Bull, de 1'Acad. Imp. de St. Petersbourg, torn. xxv. p. 549. 1879. 



(40 HABITS OF WORMS. CHAP. I. 

not been moistened by the worms, were 
pounded with a few drops of distilled water, 
and the juice thus extracted was not alkaline. 
Some leaves, however, which had been drawn 
into burrows out of doors, at an unknown 
antecedent period, were tried, and though still 
moist, they rarely exhibited even a trace of 
alkaline reaction. 

The fluid, with which the leaves are bathed, 
acts on them whilst they are fresh or nearly 
fresh, in a remarkable manner ; for it quickly 
kills and discolours them. Thus the ends of 
a fresh carrot-leaf, which had been dragged 
into a burrow, were found after twelve hours 
of a dark brown tint. Leaves of celery, 
turnip, maple, elm, lime, thin leaves of ivy, 
and occasionally those of the cabbage were 
similarly acted on. The end of a leaf of 
Triticum repens, still attached to a growing 
plant, had been drawn into a burrow, and 
this part was dark brown and dead, whilst the 
rest of the leaf was fresh and green. Several 
leaves of lime and elm removed from burrows 
out of doors were found affected in different 
degrees. The first change appears to be that 
the veins become of a dull reddish-orange. 



CHAP. I. FOOD AND DIGESTION. 41 

The cells with chlorophyll next lose more or 
less completely their green colour, and their 
contents finally become brown. The parts 
thus affected often appeared almost black by 
reflected light ; but when viewed as a trans- 
parent object under the microscope, minute 
specks of light were transmitted, arid this 
was not the case with the unaffected parts 
of the same leaves. These effects, how- 
ever, merely show that the secreted fluid is 
highly injurious or poisonous to leaves ; for 
nearly the same effects were produced in from 
one to two days on various kinds of young 
leaves, not only by artificial pancreatic fluid, 
prepared with or without thymol, but quickly 
by a solution of thymol by itself. On one 
occasion leaves of Corylus were much dis- 
coloured by being kept for eighteen hours in 
pancreatic fluid, without any thymol. With 
young and tender leaves immersion in human 
saliva during rather warm weather, acted in 
the same manner as the pancreatic fluid, but 
not so quickly. The leaves in all these 
cases often became infiltrated with the 
fluid. 

Large leaves from an ivy plant growing 



42 HABITS OF WORMS. CHAP. I. 

on a wall were so tough that they could not 
be gnawed by worms, but after four days 
they were affected in a peculiar manner by the 
secretion poured out of their mouths. The 
upper surfaces of the leaves, over which the 
worms had crawled, as was shown by the dirt 
left on them, were marked in sinuous lines, 
by either a continuous or broken chain of 
whitish and often star-shaped dots, about 
2 mm. in diameter. The appearance thus pre- 
sented was curiously like that of a leaf, into 
which the larva of some minute insect had 
burrowed. But my son Francis, after making 
and examining sections, could nowhere find 
that the cell-walls had been broken down or 
that the epidermis had been penetrated. 
When the section passed through the whitish 
dots, the grains of chlorophyll were seen to 
be more or less discoloured, and some of the 
palisade and mesophyll cells contained 
nothing but broken down granular matter. 
These effects must be attributed to the trans- 
udation of the secretion through the epidermis 
into the cells. 

The secretion with which worms moisten 
leaves likewise acts on the starch-granules 



CHAP. I. FOOD AND DIGESTION. 43 

within the cells. My son examined soma 
leaves of the ash and many of the lime, 
which had fallen off the trees and had been 
partly dragged into worm-burrows. It is- 
known that with fallen leaves the starch- 
grains are preserved in the guard-cells of the 
stomata. Now in several cases the starch had 
partially or wholly disappeared from these 
cells, in the parts which had been moistened 
by the secretion ; while it was still well pre- 
served in the other parts of the same leaves* 
Sometimes the starch was dissolved out of 
only one of the two guard-cells. The 
nucleus in one case had disappeared, together 
with the starch-granules. The mere bury- 
ing of lime-leaves in damp earth for nine 
days did not cause the destruction of the 
starch-granules. On the other hand, the im- 
mersion of fresh lime and cherry leaves for 
eighteen hours in artificial pancreatic fluid, 
led to the dissolution of the starch-granules 
in the guard-cells as well as in the other 
cells. 

From the secretion with which the leaves 
are moistened being alkaline, and from its 
acting both on the starch-granules and on 



44 HABITS OF WORMS. CHAP. I. 

the protoplasmic contents of the cells, we 
may infer that it resembles in nature not 
saliva,* but pancreatic secretion ; and we 
know from Fredericq that a secretion of this 
kind is found in the intestines of worms. As 
the leaves which are dragged into the bur- 
rows are often dry and shrivelled, it is in- 
dispensable for their disintegration by the 
unarmed mouths of worms that they should 
first be moistened and softened ; and fresh 
leaves, however soft and tender they may be, 
are similarly treated, probably from habit. 
The result is that they are partially digested 
before they are taken into the alimentary 
canal. I am not aware of any other case of 
extra-stomachal digestion having been re- 
corded. The boa-constrictor is said to bathe 
its prey with saliva, but this is doubtful ; and 
it is done solely for the sake of lubricating its 
prey. Perhaps the nearest analogy may be 
found in such plants as Drosera and Dionaea ; 
for here animal matter is digested and con- 
verted into peptone not within a stomach, but 
on the surfaces of the leaves. 

Claparede doubts whether saliva is secrete*! by worms : see 
Zeitschrift fur wissenschaft. Zoologie,' B. xix. 1869, p. 601. 



CHAP. I. CALCIFEEOUS GLANDS. 45 

Calciferous Glands. These glands (see 
Fig. 1), judging from their size and from their 
rich supply of blood-vessels, must be of much 
importance to the animal. But almost as 
many theories have been advanced on their 
use as there have been observers. They 
consist of three pairs, which in the common 
earth-worm debouch into the alimentary 
canal in advance of the gizzard, but pos- 
teriorly to it in Urochaeta and some other 
genera,* The two posterior pairs are formed 
by lamellae, which, according to Claparede, 
are diverticula from the cesophagus.f These 
lamellae are coated with a pulpy cellular 
layer, with the outer cells lying free in in- 
finite numbers. If one of these glands is 
punctured and squeezed, a quantity of white 
pulpy matter exudes, consisting of these free 
cells. They are minute, and vary in diameter 
from 2 to 6 /x. They contain in their centres 
a little excessively fine granular matter ; but 
they look so like oil globules that Claparede 



* Perrier, ' Archives de Zoolog. exper.' July, 1874, pp. 416, 
419. 

t ' Zeitschrift fur vrissenschaft. Zoologie,' B. xix. 1869, pp. 
603-606. 



46 HABITS OF WORMS. CHAP. I. 

and others at first treated them with ether. 
This produces no effect ; but they are quickly 
dissolved with effervescence in acetic acid, 
and when oxalate of ammonia is added to 
the solution a white precipitate is thrown 
down. We may therefore conclude that 
they contain carbonate of lime. If the cells 
are immersed in a very little acid, they 
become more transparent, look like ghosts, 
and are soon lost to view ; but if much acid 
is added, they disappear instantly. After a 
very large number have been dissolved, a 
flocculent residue is left, which apparently 
consists of the delicate ruptured cell-walls. 
In the two posterior pairs of glands the 
carbonate of lime contained in the cells oc- 
casionally aggregates into small rhombic 
crystals or into concretions, which lie be- 
tween the lamellae; but I have seen only 
one case, and Claparede only a very few 
such cases. 

The two anterior glands differ a little in 
shape from the four posterior ones, by being 
more oval. They differ also conspicuously in 
.generally containing several small, or two or 
three larger, or a single very large concre- 



CHAP. I. CALCIFEKOUS GLANDS. 47 

tion of carbonate of lime, as much as 1^ mm. 
in diameter. When a gland includes only 
.a few very small concretions, or, as sometimes 
happens, none at all, it is easily overlooked. 
The large concretions are round or oval, and 
exteriorly almost smooth. One was found 
which filled up not only the whole gland, as 
is often the case, but its neck ; so that it 
resembled an olive-oil flask in shape. These 
concretions when broken are seen to be 
more or less crystalline in structure. How 
they escape from the gland is a marvel ; but 
that they do escape is certain, for they are 
often found in the gizzard, intestines, and 
in the castings of worms, both with those 
kept in confinement and those in a state of 
nature. 

Claparede says very little about the 
structure of the two anterior glands, and he 
supposes that the calcareous matter of which 
the concretions are formed is derived from 
the four posterior glands. But if an anterior 
gland which contains only small concretions 
is placed in acetic acid and afterwards 
dissected, or if sections are made of such 
a gland without being treated with acid, 



48 HABITS OF "WORMS. CHAP. I. 

lamellae like those in the posterior glands 
and coated with cellular matter could be 
plainly seen, together with a multitude of 
free calciferous cells readily soluble in acetic 
acid. When a gland is completely filled with 
a single large concretion, there are no free 
cells, as these have been all consumed in 
forming the concretion. But if such a con- 
cretion, or one of only moderately large size, 
is dissolved in acid, much membranous matter 
is left, which appears to consist of the remains 
of the formerly active lamellae. After the 
formation and expulsion of a large concretion, 
new lamellae must be developed in some 
manner. In one section made by my son, the 
process had apparently commenced, although 
the gland contained two rather large concre- 
tions, for near the walls several cylindrical 
and oval pipes were intersected, which were 
lined .with cellular matter and were quite 
filled with free calciferous cells. A great 
enlargement in one direction of several oval 
pipes would give rise to the lamellae. 

Besides the free calciferous cells in which 
no nucleus was visible, other and rather 
larger free cells were seen on three occasions; 



CHAP. I. CALCIFEROUS GLANDS. 49 

and these contained a distinct nucleus and 
iiucleolus. They were only so far acted on 
by acetic acid that the nucleus was thus 
rendered more distinct. A very small con- 
cretion was removed from between two of the 
lamella? within an anterior gland. It was 
imbedded in pulpy cellular matter, with 
many free calciferous cells, together with a 
multitude of the larger, free, nucleated cells, 
and these latter cells were not acted on by 
acetic acid, while the former were dissolved. 
From this and other such cases I am led to 
suspect that the calciferous cells are developed 
from the larger nucleated ones ; but how 
this is effected was not ascertained. 

When an anterior gland contains several 
minute concretions, some of these are generally 
angular or crystalline in outline, while the 
greater number are rounded with an irregu- 
lar mulberry-like surface. Calciferous cells 
adhered to many parts of these mulberry-like 
masses, and their gradual disappearance could 
be traced while they still remained attached. 
It was thus evident that the concretions are 
formed from the lime contained within the 

E 



50 HABITS OF WORMS. CHAI-. L 

free calciferous cells. As the smaller concre- 
tions increase in size, they come into contact 
and unite, thus enclosing the now functionless 
lamellae and by such steps the formation of 
the largest concretions could be followed. 
Why the process regularly takes place in the 
two anterior glands, and only rarely in the 
four posterior glands, is quite unknown. 
Morren says that these glands disappear 
during the winter ; and I have seen some- 
instances of this fact, and others in which* 
either the anterior or posterior glands were 
at this season so shrunk and empty, that 
they could be distinguished only with muck 
difficulty. 

With respect to the function of the calci- 
ferous glands, it is probable that they pri- 
marily serve as organs of excretion, and 
secondarily as an aid to digestion. Worm& 
consume many fallen leaves ; and it is known 
that lime goes on accumulating in leaves until 
they drop off the parent-plant, instead of 
being re-absorbed into the stem or roots, like 
various other organic and inorganic sub- 
stances.* The ashes of a leaf of an acacia 

* DC Tries, ' Landwirth. Jahrbiicher,' 1881, p. 77. 



CHAP. I. CALCIFEROUS GLANDS. 51 

have been known to contain as much as 
72 per cent, of lime. Worms therefore would 
be liable to become charged with this earth, 
unless there were some special means for its 
excretion; and the calciferous glands are 
well adapted for this purpose. The worms 
which live in mould close over the chalk, 
often have their intestines filled with this 
substance, and their castings are almost white. 
Here it is evident that the supply of cal- 
careous matter must be superabundant. 
Nevertheless with several worms collected on 
such a site, the calciferous glands contained 
as many free calciferous cells, and fully as 
many and large concretions, as did the 
glands of worms which lived where there was 
little or no lime ; and this indicates that the 
lime is an excretion, and not a secretion 
poured into the alimentary canal for some 
special purpose. 

On the other hand, the following considera- 
tions render it highly probable that the 
carbonate of lime, which is excreted by the 
glands, aids the digestive process under 
ordinary circumstances. Leaves during their 

E 2 



52 HABITS OF WORMS. CHAP. I. 

decay generate an abundance of various kinds 
of acids, which have been grouped together 
under the term of humus acids. We shall 
have to recur to this subject in our fifth 
-chapter, and I need here only say that these 
acids act strongly on carbonate of lime. The 
half-decayed leaves which are swallowed in 
.such large quantities by worms would, there- 
fore, after they have been moistened and 
triturated in the alimentary canal, be apt to 
produce such acids. And in the case of 
.several worms, the contents of the alimentary 
canal were found to be plainly acid, as shown 
by litmus paper. This acidity cannot be 
.attributed to the nature of the digestive fluid, 
for pancreatic fluid is alkaline ; and we have 
seen that the secretion which is poured out of 
the mouths of worms for the sake of pre- 
paring the leaves for consumption, is likewise 
alkaline. The acidity can hardly be due to 
uric acid, as the contents of the upper part of 
the intestine were often acid. In one case 
the contents of the gizzard were slightly acid, 
those of the upper intestines being more 
plainly acid. In another case the contents of 



CHAP. I- CALCIFEROUS GLANDS. 5 

the pharynx were not acid, those of the 
gizzard doubtfully so, while those of the in- 
testine were distinctly acid at a distance of 
5 cm. below the gizzard. Even with the- 
higher herbivorous and omnivorous animals,, 
the contents of the large intestine are acid. 
" This, however, is not caused by any acid 
** secretion from the mucous membrane ; the 
" reaction of the intestinal walls in the larger 
"as in the small intestine is alkaline. It 
" must therefore arise from acid fermenta- 
** tions going on in the contents them- 

" selves In Carnivora the contents 

" of the coecum are said to be alkaline,, 
" and naturally the " amount of fermentation 
"will depend largely on the nature of the 
"food."* 

With worms not only the contents of the 
intestines, but their ejected matter or the 
castings, are generally acid. Thirty castings 
from different places were tested, and with 
three or four exceptions were found to be 
acid ; and the exceptions may have been due 

* M. Foster, 'A Text-Book of Physiology,' 2nd edit. 1878 
p. 243. 



54 HABITS OF WORMS. CHAP. I. 

to such castings not having been recently 
ejected; for some which were at first acid, 
were on the following morning, after being 
dried and again moistened, no longer acid ; 
and this probably resulted from the humus 
acids being, as is known to be the case, easily 
decomposed. Five fresh castings from worms 
which lived in mould close over the chalk, 
were of a whitish colour and abounded with 
calcareous matter; and these were not in 
the least acid. This shows how effectually 
carbonate of lime neutralises the intestinal 
acids. When worms were kept in pots filled 
with fine ferruginous sand, it was manifest 
that the oxide of iron, with which the grains 
of silex were coated, had been dissolved and 
removed from them in the castings. 

The digestive fluid of worms resembles in 
its action, as already stated, the pancreatic 
secretion of the higher animals ; and in these 
latter, " pancreatic digestion is essentially 
" alkaline ; the action will not take place 
"unless some alkali be present; and the 
" activity of an alkaline juice is arrested by 
"acidification, and hindered by neutraliza- 



CHAP. I. CALCIFEROUS GLANDS. 55 

" tion."* Therefore it seems highly probable 
that the innumerable calciferous cells, which 
:are poured from the four posterior glands 
into the alimentary canal of worms, serve to 
neutralise more or less completely the acids 
there generated by the half-decayed leaves. 
We have seen that these cells are instantly 
dissolved by a small quantity of acetic acid, 
and as they do not always suffice to neu- 
tralise the contents of even the upper part of 
the alimentary canal, the lime is perhaps 
aggregated into concretions in the anterior 
pair of glands, in order that some may be 
carried down to the posterior parts of the 
intestine, where these concretions would be 
rolled about amongst the acid contents. The 
concretions found in the intestines and in the 
castings often have a worn appearance, but 
whether this is due to some amount of 
attrition or of chemical corrosion could not 
be told. Claparede believes that they are 
formed for the sake of acting as mill-stones, 
and of thus aiding in the trituration of the 
food. They may give some aid in this way ; 

* M. Foster, ut sup. p. 200. 



56 HABITS OF WORMS. CHAP. I. 

but I fully agree with Perrfer that this must 
be of quite subordinate importance, seeing 
that the object is already attained by stones 
being generally present in the gizzards and 
intestines of worms. 



CHAPTER II. 
HABITS OF WORMS continued. 

Manner in which worms seize objects Their power of suction 
The instinct of plugging up the mouths of their burrows 
Stones piled over the burrows The advantages thus gained 
Intelligence shown by worms in their manner of plugging up 
their burrows Various kinds of leaves and other objects thus 
used Triangles of paper Summary of reasons for believing 
that worms exhibit some intelligence Means by which they 
excavate their burrows, by pushing away the earth and swal- 
lowing it Earth also swallowed for the nutritious matter 
which it contains Depth to which worms burrow, and the 
construction of their burrows Burrows lined with castings, 
and in the upper part with leaves The lowest part paved with 
little stones or seeds Manner iu which the castings arc 
ejected The collapse of old burrows Distribution of worms 
Tower-like castings in Bengal Gigantic castings on the 
Nilgiri Mountains Castings ejected in all countries. 

Ix the pots in which worms were kept, 
leaves were pinned down to the soil, and 
at night the manner in which they were 
seized could be observed. The worms always 
endeavoured to drag the leaves towards their 
burrows; and they tore or sucked off small 
fragments, whenever the leaves were stiffi- 



58 HABITS OF WORMS. CHAP. II. 

ciently tender. They generally seized the 
thin edge of a leaf with their mouths, between 
the projecting upper and lower lip ; the 
thick and strong pharynx being at the same 
time, as Perrier remarks, pushed forward 
within their bodies, so as to afford a point 
of resistance for the upper lip. In the case 
of broad flat objects they acted in a wholly 
different manner. The pointed anterior 
extremity of the body, after being brought 
into contact with an object of this kind, was 
drawn within the adjoining rings, so that it 
appeared truncated and became as thick as 
the rest of the body. This part could then 
be seen to swell a little ; and this, I believe, 
is due to the pharynx being pushed a little 
forwards. Then by a slight withdrawal of 
the pharynx or by its expansion, a vacuum 
was produced beneath the truncated slimy 
end of the body whilst in contact with the 
object; and by this means the two adhered 
firmly together.* That under these circum- 
stances a vacuum was produced was plainly 

* Claparfede remarks (' Zeitschrift fur wissenschaft. Zoolog.' 
B. 19, 18G9, p. 602) that the pharynx appears from its structure 
to be adapted for suction. 



CHAP. II. THEIR MANNER OF PREHENSION. 59 

seen on one occasion, when a large worm 
lying beneath a flaccid cabbage leaf tried to 
drag it away ; for the surface of the leaf 
directly over the end of the worm's body 
became deeply pitted. On another occasion 
a worm suddenly lost its hold on a flat leaf; 
and the anterior end of the body was momen- 
tarily seen to be cup-formed. Worms can 
attach themselves to an object beneath water 
in the same manner; and I saw one thus 
dragging away a submerged slice of an 
onion-bulb. 

The edges of fresh or nearly fresh leaves 
affixed to the ground were often nibbled by 
the worms ; and sometimes the epidermis and 
all the parenchyma on one side was gnawed 
completely away over a considerable space ; 
the epidermis alone on the opposite side 
being left quite clean. The veins were 
never touched, and leaves were thus some- 
times partly converted into skeletons. As 
worms have no teeth and as their mouths 
consist of very soft tissue, it may be pre- 
sumed that they consume by means of suction 
the edges and the parenchyma of fresh 
leaves, after they have been softened by the 



60 HABITS OF WORMS. CHAP. IL 

digestive fluid. They cannot attack such 
strong leaves as those of sea-kale or large 
and thick leaves of ivy ; though one of the 
latter after it had become rotten was reduced 
in parts to the state of a skeleton. 

Worms seize leaves and other objects, not 
only to serve as food, but for plugging up 
the mouths of their burrows ; and this is 
one of their strongest instincts. They some- 
times work so energetically that Mr. D. F. 
Simpson, who has a small walled garden 
where worms abound in Bayswater, informs 
me that on a calm damp evening he there 
heard so extraordinary a rustling noise from 
under a tree from which many leaves had 
fallen, that he went out with a light and dis- 
covered that the noise was caused by many 
worms dragging the dry leaves and squeezing 
them into the burrows. Not only leaves, but 
petioles of many kinds, some flower-pedun- 
cles, often decayed twigs of trees, bits of 
paper, feathers, tufts of wool and horse-hairs 
are dragged into their burrows for this pur- 
pose. I have seen as many as seventeen 
petioles of a Clematis projecting from the 
mouth of one burrow, and ten from the 



CHAP. II. PROTECTION OF THEIR BURROWS. 61 

mouth of another. Some of these objects, 
such as the petioles just named, feathers, &c., 
are never gnawed by worms. In a gravel- 
walk in my garden I found many hundred 
leaves of a pine-tree (P. austriaca or nigri- 
^ans) drawn by their bases into burrows. 
The surfaces by which these leaves are articu- 
lated to the branches are shaped in as pecu- 
liar a manner as is the joint between the leg- 
bones of a quadruped ; and if these surfaces 
had been in the least gnawed, the fact would 
have been immediately visible, but there was 
no trace of gnawing. Of ordinary dicotyle- 
donous leaves, all those which are dragged 
into burrows are not gnawed. I have seen 
as many as nine leaves of the lime-tree 
drawn into the same burrow, and not nearly 
all of them had been gnawed ; but such 
leaves may serve as a store for future con- 
sumption. Where fallen leaves are abun- 
dant, many more are sometimes collected 
over the mouth of a burrow than can be 
used, so that a small pile of unused leaves is 
left like a roof over those which have been 
partly dragged in. 

A leaf in being dragged a little way into 



62 HABITS OF WORMS. CHAP. IL 

a cylindrical burrow is necessarily much 
folded or crumpled. When another leaf is. 
drawn in, this is done exteriorly to the first 
one, and so on with the succeeding leaves ; and 
finally all become closely folded and pressed 
together. Sometimes the worm enlarges the 
mouth of its burrow, or makes a fresh one 
close by, so as to draw in a still larger number 
of leaves. They often or generally fill up the 
interstices between the drawn-in leaves with 
moist viscid earth ejected from their bodies; 
and thus the mouths of the burrows are 
securely plugged. Hundreds of such plugged 
burrows may be seen in many places,, 
especially during the autumnal and early 
winter months. But, as will hereafter be 
shown, leaves are dragged into the burrows- 
not only for plugging them up and for food, 
but for the sake of lining the upper part or 
mouth. 

When worms cannot obtain leaves, petioles, 
sticks, &c., with which to plug up the mouths: 
of their burrows, they often protect them by 
little heaps of stones; and such heaps of 
smooth rounded pebbles may frequently be 
seen on gravel-walks. Here there can be no 



CHAP. II. PROTECTION OF THEIR BURROWS. 63 

question about food. A lady, who was in- 
terested in the habits of worms, removed the 
little heaps of stones from the mouths of 
several burrows and cleared the surface of the 
ground for some inches all round. She went 
out on the following night with a lantern, 
and saw the worms with their tails fixed in 
their burrows, dragging the stones inwards 
by the aid of their mouths, no doubt by 
suction. "After two nights some of the- 
" holes had 8 or 9 small stones over 
" them ; after four nights one had about 
" 30, and another 34 stones."* One stone 
which had been dragged over the gravel-walk 
to the mouth of a burrow weighed two- 
ounces; and this proves how strong worms 
are. But they show greater strength in some- 
times displacing stones in a well-trodden 
gravel-walk ; that they do so, may be inferred 
from the cavities left by the displaced stones 
being exactly filled by those lying over the 
mouths of adjoining burrows, as I have my- 
self observed. 

Work of this kind is usually performed 

* An account of her observations is given in the ' Gardeners 1 
Chronicle,' March 28th, 1868, p. 324. 



61 HABITS OF WORMS. CHAP. II. 

during the night ; but I have occasionally 
known objects to be drawn into the burrows 
during the day. What advantage the worms 
derive from plugging up the mouths of their 
burrows with leaves, &c., or from piling 
stones over them, is doubtful. They do not 
act in this manner at the times when they 
eject much earth from their burrows ; for their 
castings then serve to cover the mouths. 
When gardeners wish to kill worms on a 
lawn, it is necessary first to brush or rake 
away the castings from the surface, in order 
that the lime-water may enter the burrows.* 
It might be inferred from this fact that the 
mouths are plugged up with leaves, &c., to 
prevent the entrance of water during heavy 
rain ; but it may be urged against this view 
that a few, loose, well-rounded stones are ill- 
adapted to keep out water. I have moreover 
seen many burrows in the perpendicularly 
cut turf-edgings to gravel-walks, into which 
water could hardly flow, as well plugged as 
burrows on a level surface. It is not probable 
that the plugs or piles of stones serve to 
conceal the burrows from scolopendras, which, 

* London's ' Card. Mag.' xvii. p. 210, as quoted in the ' Cata- 
logue of the British Museum Wonts,' 1865, p. 327. 



CHAP. H. PROTECTION OF THEIE BURROWS. 65 

according to Hoffmeister, * are the bitterest 
enemies of worms, or from the larger species 
of Carabus and Staphylinus which attack them 
ferociously, for these animals are nocturnal, 
and the burrows are opened at night. May 
not worms when the mouth of the burrow is 
protected be able to remain with safety with 
their heads close to it, which we know that they 
like to do, but which costs so many of them 
their lives ? Or may not the plugs check the 
free ingress of the lowest stratum of air, when 
chilled by radiation at night, from the sur- 
rounding ground and herbage ? I am inclined 
to believe in this latter view : firstly, because 
when worms were kept in pots in a room with 
a fire, in which case cold air could not enter the 
burrows, they plugged them up in a slovenly 
manner ; and secondarily, because they often 
coat the upper part of their burrows with 
leaves, apparently to prevent their bodies from 
coming into close contact with the cold damp 
earth. Mr. E. Parfitt has suggested to me 
that the mouths of the burrows are closed in 
order that the air within them may be kept 
thoroughly damp, and this seems the most 
probable explanation of the habit. But the 

* ' Familie der Regenwurmer,' p. 19. 

F 



66 HABITS OF WOEMS. CHAP. II. 

plugging-up process may serve for all the 
above purposes. 

Whatever the motive may be, it appears 
that worms much dislike leaving the mouths 
of their burrows open. Nevertheless they 
will reopen them at night, whether or not 
they can afterwards close them. Numerous 
open burrows may be seen on recently-dug 
ground, for in this case the worms eject their 
castings in cavities left in the ground, or in 
the old burrows instead of piling them over 
the mouths of their burrows, and they cannot 
collect objects on the surface by which the 
mouths might be protected. So again on a 
recently disinterred pavement of a Roman 
villa at Abinger (hereafter to be described) 
the worms pertinaciously opened their bur- 
rows almost every night, when these had 
been closed by being trampled on, although 
they were rarely able to find a few minute 
stones wherewith to protect them. 

Intelligence shown by worms in their manner 
of plugging up their burrows. If a man had to 
plug up a small cylindrical hole, with such 
objects as leaves, petioles or twigs, he would 
drag or push them in by their pointed ends ; 



CHAP. II. THEIR INTELLIGENCE. 67 

but if these objects were very thin relatively 
to the size of the hole, he would probably 
insert some by their thicker or broader ends. 
The guide in his case would be intelligence. 
It seemed therefore worth while to observe 
carefully how worms dragged leaves into 
their burrows; whether by their tips or 
bases or middle parts. It seemed more espe- 
cially desirable to do this in the case of plants 
not natives to our country ; for although the 
habit of dragging leaves into their burrows 
is undoubtedly instinctive with worms, yet 
instinct could not tell them how to act in 
the case of leaves about which their pro- 
genitors knew nothing. If, moreover, worms 
acted solely through instinct or an unvary- 
ing inherited impulse, they would draw all 
kinds of leaves into their burrows in the 
same manner. If they have no such definite 
instinct, we might expect that chance would 
determine whether the tip, base or middle was 
seized. If both these alternatives are ex- 
cluded, intelligence alone is left ; unless the 
worm in each case first tries many different 
methods, and follows that alone which 
proves possible or the most easy ; but to act 

G 



68 HABITS OF WORMS. CHAP. II. 

in this manner and to try different methods 
makes a near approach to intelligence. 

In the first place 227 withered leaves of 
various kinds, mostly of English plants, were 
pulled out of worm-burrows in several places. 
Of these, 181 had been drawn into the 
burrows by or near their tips, so that the 
foot-stalk projected nearly upright from the 
mouth of the burrow ; 20 had been drawn in 
by their bases, and in this case the tips pro- 
jected from the burrows ; and 26 had been 
seized near the middle, so that these had 
been drawn in transversely and were much 
crumpled. Therefore 80 per cent, (always 
using the nearest whole number) had been 
drawn in by the tip, 9 per cent, by the base 
or foot-stalk, and 1 1 per cent, transversely or 
by the middle. This alone is almost suffi- 
cient to show that chance does not determine 
the manner in which leaves are dragged into 
the burrows. 

Of the above 227 leaves, 70 consisted of 
the fallen leaves of the common lime-tree, 
which is almost certainly not a native of 
England. These leaves are much acumin- 
ated towards the tip, and are very broad at 



CHAP. II. THEIE INTELLIGENCE. 69 

the base with a well-developed foot-stalk. 
They are thin and quite flexible when half- 
withered. Of the 70, 79 per cent, had been 
drawn in by or near the tip; 4 per cent, 
by or near the base ; and 17 per cent, trans- 
versely or by the middle. These proportions 
agree very closely, as far as the tip is con- 
cerned, with those before given. But the per- 
centage drawn in by the base is smaller, which 
may be attributed to the breadth of the basal 
part of the blade. We here, also, see that the 
presence of a foot-stalk, which it might have 
been expected would have tempted the worms 
as a convenient handle, has little or no in- 
fluence in determining the manner in which 
lime leaves are dragged into the burrows. 
The considerable proportion, viz., 17 per 
cent., drawn in more or less transversely 
depends no doubt on the flexibility of these 
half-decayed leaves. The fact of so many 
having been drawn in by the middle, and of 
some few having been drawn in by the base, 
renders it improbable that the worms first 
tried to draw in most of the leaves by one or 
both of these methods, and that they after- 
wards drew in 79 per cent, by their tips ; 

G 2 



70 HABITS OF WORMS. CHAP. II. 

for it is clear that they would not have failed 
in drawing them in by the base or middle. 

The leaves of a foreign plant were next 
searched for, the blades of which were not 
more pointed towards the apex than towards 
the base. This proved to be the case with 
those of a laburnum (a hybrid between 
Cytisus alpinus and laburnum) for on doubling 
the terminal over the basal half, they gene- 
rally fitted exactly ; and when there was 
any difference, the basal half was a little the 
narrower. It might, therefore, have been 
expected that an almost equal number of 
these leaves would have been drawn in by the 
tip and base, or a slight excess in favour of 
the latter. But of 73 leaves (not included in 
the first lot of 227) pulled out of worm- 
burrows, 63 per cent, had been drawn in by 
the tip ; 27 per cent, by the base, and 10 per 
cent, transversely. We here see that a far 
larger proportion, viz., 27 per cent, were 
drawn in by the base than in the case of 
lime leaves, the blades of which are very 
broad at the base, and of which only 4 per 
cent, had thus been drawn in. We may 
perhaps account for the fact of a still larger 



CHAP. II. THEIR INTELLIGENCE. 71 

proportion of the laburnum leaves not hav- 
ing been drawn in by the base, by worms 
having acquired the habit of generally drawing 
in leaves by their tips and thus avoiding the 
foot-stalk. For the basal margin of the blade 
in many kinds of leaves forms a large angle 
with the foot-stalk ; and if such a leaf were 
drawn in by the foot-stalk, the basal margin 
would come abruptly into contact with the 
ground on each side of the burrow, and would 
render the drawing in of the leaf very difficult. 
Nevertheless worms break through their 
habit of avoiding the foot-stalk, if this part 
offers them the most convenient means for 
drawing leaves into their burrows. The leaves 
of the endless hybridised varieties of the 
Rhododendron vary much in shape ; some are 
narrowest towards the base and others to- 
wards the apex. After they have fallen off, 
the blade on each side of the midrib often 
becomes curled up while drying, sometimes 
along the whole length, sometimes chiefly 
at the base, sometimes towards the apex. 
Out of 28 fallen leaves on one bed of peat in 
my garden, no less than 23 were narrower in 
the basal quarter than in the terminal quarter 
of their length; and this narrowness was 



72 HABITS OF WOEMS. OHAP. U. 

chiefly due to the curling in of the margins. 
Out of 36 fallen leaves on another bed, in 
which different varieties of the Rhododendron 
grew, only 17 were narrower towards the 
hase than towards the apex. My son William, 
who first called my attention to this case, 
picked up 237 fallen leaves in his garden 
(where the Rhododendron grows in the 
natural soil) and of these 65 per cent, could 
have been drawn by worms into their bur- 
rows more easily by the base or foot-stalk 
than by the tip ; and this was partly due to 
the shape of the leaf and in a less degree 
to the curling in of the margins: 27 per 
cent, could have been drawn in more easily 
by the tip than by the base : and 8 per cent. 
with about equal ease by either end. The 
shape of a fallen leaf ought to be judged 
of before one end has been drawn into a 
burrow, for after this has happened, the free 
end, whether it be the base or apex, will dry 
more quickly than the end embedded in the 
damp ground ; and the exposed margins of 
the free end will consequently tend to become 
more curled inwards than they were when 
the leaf was first seized by the worm. My 
son found 91 leaves which had been dragged 



CHAP. II. THEIR INTELLIGENCE. 73 

by worms into their burrows, though not to a 
great depth ; of these 66 per cent, had been 
drawn in by the base or foot-stalk ; and 34 
per cent, by the tip. In this case, therefore, 
the worms judged with a considerable degree 
of correctness how best to draw the withered 
leaves of this foreign plant into their burrows ; 
notwithstanding that they had to depart from 
their usual habit of avoiding the foot-stalk. 

On the gravel-walks in my garden a very 
large number of leaves of three species of 
Pinus (P. austriaca, nigricans and sylvestris) 
are regularly drawn into the mouths of worm- 
burrows. These leaves consist of two so-called 
needles, which are of considerable length in the 
two first and short in the last named species, 
and are united to a common base ; and it is by 
this part that they are almost invariably drawn 
into the burrows. I have seen only two or 
at most three exceptions to this rule with 
worms in a state of nature. As the sharply 
pointed needles diverge a little, and as several 
leaves are drawn into the same burrow, each 
tuft forms a perfect chevaux de /rise. On two- 
occasions many of these tufts were pulled up 
in the evening, but by the following morning 
fresh leaves had been pulled in, and the 



74 HABITS OF WORMS. CHAP. II. 

burrows were again well protected. These 
leaves could not be dragged into the burrows 
to any depth, except by their bases, as a 
worm cannot seize hold of the two needles at 
the same time, and if one alone were seized 
by the apex, the other would be pressed 
against the ground and would resist the 
entry of the seized one. This was manifest 
in the above mentioned two or three excep- 
tional cases. In order, therefore, that worms 
should do their work well, they must drag 
pine-leaves into their burrows by their bases, 
where the two needles are conjoined. But 
how they are guided in this work is a per- 
plexing question. 

This difficulty led my son Francis and my- 
self to observe worms in confinement during 
several nights by the aid of a dim light, while 
they dragged the leaves of the above named 
pines into their burrows. They moved the 
anterior extremities of their bodies about the 
leaves, and on several occasions when they 
touched the sharp end of a needle they with- 
drew suddenly as if pricked. But I doubt 
whether they were hurt, for they are indif- 
ferent to very sharp objects, and will swallow 
even rose-thorns and small splinters of glass. 



CHAP. II. THEIK INTELLIGENCE. 75 

It may also be doubted, whether the sharp 
ends of the needles serve to tell them that 
this is the wrong end to seize ; for the points 
were cut off many leaves for a length of 
about one inch, and fifty-seven of them thus 
treated were drawn into the burrows by 
their bases, and not one by the cut-off ends. 
The worms in confinement often seized the 
needles near the middle and drew them to- 
wards the mouths of their burrows ; and one 
worm tried in a senseless manner to drag 
them into the burrow by bending them. 
They sometimes collected many more leaves 
over the mouths of their burrows (as in the 
case formerly mentioned of lime-leaves) than 
could enter them. On other occasions, how- 
ever, they behaved very differently; for as 
soon as they touched the base of a pine-leaf, 
this was seized, being sometimes completely en- 
gulfed in their mouths, or a point very near 
the base was seized, and the leaf was then 
quickly dragged or rather jerked into their 
burrows. It appeared both to my son and 
myself as if the worms instantly perceived 
as soon as they had seized a leaf in the proper 
manner. Nine such cases were observed, 
but in one of them the worm failed to drag 



76 HABITS OF WORMS. CHAP. II. 

the leaf into its burrow, as it was entangled 
by other leaves lying near. In another case 
a leaf stood nearly upright with the points of 
the needles partly inserted into a burrow, but 
how placed there was not seen ; and then the 
worm reared itself up and seized the base,, 
which was dragged into the mouth of the 
burrow by bowing the whole leaf. On the 
other hand, after a worm had seized the base 
of a leaf, this was on two occasions relin- 
quished from some unknown motive. 

As already remarked, the habit of plugging 
up the mouths of the burrows with various 
objects, is no doubt instinctive in worms ; 
and a very young one, born in one of my 
pots, dragged for some little distance a Scotch- 
fir leaf, one needle of which was as long and 
almost as thick as its own body. No species 
of pine is endemic in this part of England, 
it is therefore incredible that the proper 
manner of dragging pine-leaves into the 
burrows can be instinctive with our worms. 
But as the worms on which the above obser- 
vations were made, were dug up beneath or 
near some pines, which had been planted 
there about forty years, it was desirable to 
prove that their actions were not instinctive. 



CHAP. II. THEIK INTELLIGENCE. 77 

Accordingly, pine-leaves were scattered on 
the ground in places far removed from any 
pine-tree, and 90 of them were drawn into 
the burrows by their bases. Only two were 
drawn in by the tips of the needles, and these 
were not real exceptions, as one was drawn 
in for a very short distance, and the two 
needles of the other cohered. Other pine- 
leaves were given to worms kept in pots in a 
warm room, and here the result was different ; 
for out of 42 leaves drawn into the burrows, 
no less than 16 were drawn in by the tips 
of the needles. These worms, however, 
worked in a careless or slovenly manner ; 
for the leaves were often drawn in to only 
a small depth ; sometimes they were merely 
heaped over the mouths of the burrows, and 
sometimes none were drawn in. I believe 
that this carelessness may be accounted for 
either by the warmth of the air, or by its 
dampness, as the pots were covered by glass 
plates ; the worms consequently did not care 
about plugging up their holes effectually. Pots 
tenanted by worms and covered with a net 
which allowed the free entrance of air, were 
left out of doors for several nights, and now 72 
leaves were all properly drawn in by their bases. 



78 HABITS OF WORMS. CHAP. IL 

It might perhaps be inferred from the facts 
as yet given, that worms somehow gain a 
general notion of the shape or structure of 
pine-leaves, and perceive that it is necessary 
for them to seize the base where the two 
needles are conjoined. But the following 
cases make this more than doubtful. The 
tips of a large number of needles of P. austriaca 
were cemented together with shell-lac dis- 
solved in alcohol, and were kept for some 
days, until, as I believe, all odour or taste had 
been lost; and they were then scattered on 
the ground where no pine-trees grew, near 
burrows from which the plugging had been 
removed. Such leaves could have been drawn 
into the burrows with equal ease by either 
end ; and judging from analogy and more 
especially from the case presently to be given 
of the petioles of Clematis montana, I expected 
that the apex would have been preferred. 
But the result was that out of 121 leaves with 
the tips cemented, which were drawn into bur- 
rows, 108 were drawn in by their bases, and 
only 13 by their tips. Thinking that the 
worms might possibly perceive and dislike the 
smell or taste of the shell-lac, though this 
was very improbable, especially after the 



CHAP. II. THEIR INTELLIGENCE. 79 

leaves had been left out during several nights, 
the tips of the needles of many leaves were 
tied together with fine thread. Of leaves 
thus treated 150 were drawn into burrows 
123 by the base and 27 by the tied tips; so 
that between four and five times as many were 
drawn in by the base as by the tip. It is 
possible that the short cut-off ends of the 
thread with which they were tied, may have 
tempted the worms to drag in a larger propor- 
tional number by the tips than when cement 
was used. Of the leaves with tied and 
cemented tips taken together (271 in number) 
85 per cent, were drawn in by the base and 
15 per cent, by the tips. We may therefore 
infer that it is not the divergence of the two 
needles which leads worms in a state of nature 
almost invariably to drag pine-leaves into 
their burrows by the base. Nor can it be the 
sharpness of the points of the needles which 
determines them ; for, as we have seen, many 
leaves with the points cut off were drawn in 
by their bases. "We are thus led to conclude, 
that with pine-leaves there must be something 
attractive to worms in the base, notwithstand- 
ing that few ordinary leaves are drawn in by 
the base or foot-stalk. 



80 HABITS OF WOKMS. CHAP. II. 

Petioles. We will now turn to the petioles 
or foot-stalks of compound leaves, after the 
leaflets have fallen off. Those from Clematis 
montana, which grew over a verandah, were 
dragged early in January in large numbers 
into the burrows on an adjoining gravel- 
walk, lawn, and flower-bed. These petioles 
vary from 2J to 4j inches in length, are 
rigid and of nearly uniform thickness, except 
close to the base where they thicken rather 
abruptly, being here about twice as thick as 
in any other part. The apex is somewhat 
pointed, but soon withers and is then easily 
broken off. Of these petioles, 314 were pulled 
out of burrows in the above specified sites; 
and it was found that 76 per cent, had been 
drawn in by their tips, and 24 per cent, by 
their bases ; so that those drawn in by the 
tip were a little more than thrice as many 
as those drawn in by the base. Some of those 
extracted from the well-beaten gravel-walk 
were kept separate from the others; and of 
these (59 in number) nearly five times as 
many had been drawn in by the tip as by 
the base; whereas of those extracted from 
the lawn and flower-bed, where from the 
soil yielding more easily, less care would be 



CHAP. II. THEIR INTELLIGENCE. 81 

necessary in plugging up the burrows, the 
proportion of those drawn in by the tip (130) 
to those drawn in by the base (48) was 
rather less than three to one. That these 
petioles had been dragged into the burrows 
for plugging them up, and not for food, 
was manifest, as neither end, as far as I 
could see, had been gnawed. As several 
petioles are used to plug up the same burrow, 
in one case as many as 10, and in another 
case as many as 15, the worms may perhaps 
at first draw in a few by the thicker end so 
as to save labour; but afterwards a large 
majority are drawn in by the pointed end, in 
order to plug up the hole securely. 

The fallen petioles of our native ash-tree 
were next observed, and the rule with most 
objects, viz., that a large majority are dragged 
into the burrows by the more pointed end, had 
not here been followed; and this fact much 
surprised me at first. These petioles vary in 
length from 5 to 8^ inches ; they are thick 
and fleshy towards the base, whence they 
taper gently towards the apex, which is a little 
enlarged and truncated where the terminal 
leaflet had been originally attached. Under 
some ash-trees growing in a grass-field, 229 



82 HABITS OP WORMS. CHAP. II. 

petioles were pulled out of worm burrows 
early in January, and of these 5T5 per cent, 
had been drawn in by the ba.se, and 48 '5 per 
cent, by the apex. This anomaly was how- 
ever readily explained as soon as the thick 
basal part was examined ; for in 78 out of 103 
petioles, this part had been gnawed by worms, 
just above the horse-shoe shaped articulation. 
In most cases there could be no mistake about 
the gnawing ; for ungnawed petioles which 
were examined after being exposed to the 
weather for eight additional weeks had not 
become more disintegrated or decayed near 
the base than elsewhere. It is thus evident 
that the thick basal end of the petiole is 
drawn in not solely for the sake of plugging 
up the mouths of the burrows, but as food. 
Even the narrow truncated tips of some 
few petioles had been gnawed ; and this 
was the case in 6 out of 37 which were 
examined for this purpose. Worms, after 
having drawn in and gnawed the basal end, 
often push the petioles out of their burrows ; 
and then drag in fresh ones, either by 
the base for food, or by the apex for plug- 
ging up the mouth more effectually. Thus, 
out of 37 petioles inserted by their tips, 



CHAP. II. THEIK INTELLIGENCE. 83 

5 had been previously drawn in by tne- 
base, for this part had been gnawed. Again,. 
I collected a handful of petioles lying loose 
on the ground close to some plugged-up bur- 
rows, where the surface was thickly strewed 
with other petioles which apparently had 
never been touched by worms; and 14 out 
of 47 (i.e. nearly one-third), after having 
had their bases gnawed had been pushed 
out of the burrows and were now lying on 
the ground. From these several facts we may 
conclude that worms draw in some petioles 
of the ash by the base to serve as food, and 
others by the tip to plug up the mouths of 
their burrows in the most efficient manner. 

The petioles of Robinia pseudo-acacia vary 
from 4 or 5 to nearly 12 inches in length; 
they are thick close to the base before the 
softer parts have rotted off, and taper much 
towards the upper end. They are so flexible 
that I have seen some few doubled up and 
thus drawn into the burrows of worms. Un- 
fortunately these petioles were not examined 
until February, by which time the softer parts 
had completely rotted off, so that it was im- 
possible to ascertain whether worms had 

H 



84 HABITS OF WORMS. CHAP. IL 

gnawed the bases, though this is in itself 
probable. Out of 121 petioles extracted from 
burrows early in February, 68 were imbedded 
by the base, and 53 by the apex. On 
February 5 all the petioles which had been 
drawn into the burrows beneath a Robinia, 
were pulled up ; and after an interval of 
eleven days, 35 petioles had been again 
dragged in, 19 by the base, and 16 by the 
apex. Taking these two lots together, 56 
per cent, were drawn in by the base, and 44 
per cent, by the apex. As all the softer parts 
had long ago rotted off, we may feel sure, 
especially in the latter case, that none had 
been drawn in as food. At this season, there- 
fore, worms drag these petioles into their 
burrows indifferently by either end, a slight 
preference being given to the base. This 
latter fact may be accounted for by the diffi- 
culty of plugging up a burrow with objects so 
extremely thin as are the upper ends. In 
support of this view, it may be stated that out 
of the 16 petioles which had been drawn 
in by their upper ends, the more attenuated 
terminal portion of 7 had been previously 
broken off by some accident. 



CHAP. H. THEIR INTELLIGENCE. 85 

Triangles of paper. Elongated triangles 
were cut out of moderately stiff writing-paper, 
which was rubbed with raw fat on both sides,, 
so as to prevent their becoming excessively 
limp when exposed at night to rain and dew. 
The sides of all the triangles were three 
inches in length, with the bases of 120 one 
inch, and of the other 183 half an inch in 
length. These latter triangles were very 
narrow or much acuminated.* As a check 
on the observations presently to be given,, 
similar triangles in a damp state were seized 
by a very narrow pair of pincers at different 
points and at all inclinations with reference 
to the margins, and were then drawn into 
a short tube of the diameter of a worm- 
burrow. If seized by the apex, the triangle 
was drawn straight into the tube, with its 
margins infolded; if seized at some little 
distance from the apex, for instance at half 
an inch, this much was doubled back within 
the tube. So it was with the base and basal 
angles, though in this case the triangles 
offered, as might have been expected, much 

*' In these narrow triangles the apical angle is 9 34', and the 
"basal angles 85 13'. In the broader triangles the apical angle is 
19 Itf and the basal angles 80 25'. 

H 2 



86 HABITS OF WORMS. CHAP. IL 

more resistance to being drawn in. If seized 
near the middle the triangle was doubled up, 
with the apex and base left sticking out of the 
tube. As the sides of the triangles were 
three inches in length, the result of their 
being drawn into a tube or into a burrow in 
different ways, may be conveniently divided 
into three groups : those drawn in by the 
apex or within an inch of it ; those drawn in 
by the base or within an inch of it ; and those 
drawn in by any point in the middle inch. 

In order to see how the triangles would be 
seized by worms, some in a damp state were 
given to worms kept in confinement. They 
were seized in three different manners in the 
case of both the narrow and broad triangles : 
viz., by the margin ; by one of the three 
angles, which was often completely engulfed 
in their mouths ; and lastly, by suction applied 
to any part of the flat surface. If lines 
parallel to the base and an inch apart, are 
drawn across a triangle with the sides three 
inches in length, it will be divided into three 
parts of equal length. Now if worms seized 
indifferently by chance any part, they 
would assuredly seize on the basal part or 



CHAP. II. THEIR INTELLIGENCE. 87 

division far oftener than on either of the two 
other divisions. For the area of the basal to 
the apical part is as 5 to 1, so that the 
chance of the former being drawn into a 
burrow by suction, will be as 5 to 1, compared 
with the apical part. The base offers two 
angles and the apex only one, so that the 
former would have twice as good a chance 
(independently of the size of the angles) of 
being engulfed in a worm's mouth, as would 
the apex. It should, however, be stated that 
the apical angle is not often seized by worms ; 
the margin at a little distance on either side 
being preferred. I judge of this from having 
found in 40 out of 46 cases in which tri- 
angles had been drawn into burrows by their 
apical ends, that the tip had been doubled 
back within the burrow for a length of 
between Joth of an inch and 1 inch. Lastly, 
the proportion between the margins of the basal 
and apical parts is as 3 to 2 for the broad, 
and 2 1 to 2 for the narrow triangles. From 
these several considerations it might certainly 
have been expected, supposing that worms 
seized hold of the triangles by chance, that a 
considerably larger proportion would have 



88 HABITS OF WORMS. CHAP. II. 

been dragged into the burrows by the basal 
than by the apical part; but we shall im- 
mediately see how different was the result. 

Triangles of the above specified sizes were 
scattered on the ground in many places and 
on many successive nights near worm-bur- 
rows, from which the leaves, petioles, twigs, 
&c., with which they had been plugged, were 
removed. Altogether 303 triangles were 
drawn by worms into their burrows : 12 others 
were drawn in by both ends, but as it was im- 
possible to judge by which end they had been 
first seized, these are excluded. Of the 303, 
62 per cent, had been drawn in by the apex 
(using this term for all drawn in by the 
apical part, one inch in length) ; 15 per cent, 
by the middle ; and 23 per cent, by the basal 
part. If they had been drawn indifferently 
by any point, the proportion for the apical, 
middle and basal parts would have been 3 3' 3 
per cent, for each ; but, as we have just seen, 
it might have been expected that a much 
larger proportion would have been drawn in 
by the basal than by any other part. As the 
case stands, nearly three times as many were 
drawn in by the apex as by the base. If we 



CHAP. II. THEIK INTELLIGENCE. 89 

consider the broad triangles by themselves, 
59 per cent, were drawn in by the apex, 25 
per cent, by the middle, and 16 per cent, by 
the base. Of the narrow triangles, 65 per 
cent, were drawn in by the apex, 14 per cent, 
by the middle, and 21 per cent, by the base ; 
so that here those drawn in by the apex were 
more than 3 times as many as those drawn 
in by the base. We may therefore conclude 
that the manner in which the triangles are 
drawn into the burrows is not a matter of 
chance. 

In eight cases, two triangles had been drawn 
into the same burrow, and in seven of these 
cases, one had been drawn in by the apex and 
the other by the base. This again indicates 
that the result is not determined by chance. 
Worms appear sometimes to revolve in the 
act of drawing in the triangles, for five out of 
the whole lot had been wound into an irregular 
spire round the inside of the burrow. Worms 
kept in a warm room drew 63 triangles 
into their burrows ; but, as in the case of the 
pine-leaves, they worked in a rather careless 
manner, for only 44 per cent, were drawn in 
by the apex, 22 per cent, by the middle, and 



90 HABITS OF WORMS. CHAP. II. 

33 per cent, by the base. In five cases, two 
triangles were drawn into the same burrow. 

It may be suggested with much apparent 
probability that so large a proportion of the 
triangles were drawn in by the apex, not from 
the worms having selected this end as the 
most convenient for the purpose, but from 
having first tried in other ways and failed. 
This notion was countenanced by the manner 
in which worms in confinement were seen to 
drag about and drop the triangles ; but then 
they were working carelessly. I did not at 
first perceive the importance of this subject, 
but merely noticed that the bases of those tri- 
angles which had been drawn in by the apex, 
were generally clean and not crumpled. The 
subject was afterwards attended to carefully. 
In the first place several triangles which had 
been drawn in by the basal angles, or by the 
base, or a little above the base, and which 
were thus much crumpled and dirtied, were 
left for some hours in water and were then 
well shaken while immersed ; but neither 
the dirt nor the creases were thus removed. 
Only slight creases could be obliterated, 
even by pulling the wet triangles several 



CHAP. II. THEIE INTELLIGENCE. 91 

times through my fingers. Owing to the 
slime from the worms' bodies, the -dirt was 
not easily washed off. We may therefore 
conclude that if a triangle, before being 
dragged in by the apex, had been dragged 
into a burrow by its base with even a slight 
degree of force, the basal part would long 
retain its creases and remain dirty. The con- 
dition of 89 triangles (65 narrow and 24 
broad ones), which had been drawn in by the 
apex, was observed ; and the bases of only 7 
of them were at all creased, being at the same 
time generally dirty. Of the 82 uncreased 
triangles, 14 were dirty at the base ; but it 
does not follow from this fact that these had 
first been dragged towards the burrows by 
their bases ; for the worms sometimes covered 
large portions of the triangles with slime, 
and these when dragged by the apex over the 
ground would be dirtied ; and during rainy 
weather, the triangles were often dirtied over 
one whole side or over both sides. If the 
worms had dragged the triangles to the 
mouths of their burrows by their bases, as often 
as by their apices, and had then perceived, 
without actually trying to draw them into the 






92 



HABITS OF WORMS. 



CHAP. II. 



burrow, that the broader end was not well 
adapted for this purpose even in this case 
a large proportion would probably have had 
their basal ends dirtied. We may therefore 
infer improbable as is the inference that 
worms are able by some means to judge 
which is the best end by which to draw 
triangles of paper into their burrows. 

The percentage results of the foregoing ob- 
servations on the manner in which worms 
draw various kinds of objects into the mouths 
of their burrows may be abridged as follows : 





Drawn 








into the 


Drawn 


Drawn 


Nature of Object. 


burrows, 
by or 


in, by or 
near the 


in, by or 
near the 




near the 


middle. 


base. 




apex. 






Leaves of various kinds . . : 


80 


11 


9 


of the Lime, basal margin of 








"blade broad, apex acumi- 








nated . . . . 


79 


17 


4 


of a Laburnum, basal part of 








blade as narrow as, or some- 








times little narrower than 








the apical part. 


63 


10 


27 


of the Rhododendron, basal 








part of blade often narrower 
than the apical part . 


34 


,, 


GG 


*f ~D: i 1 **e A. 








needles arising from a com- 


mon base 






100 



CHAP. II. 



THEIR INTELLIGENCE. 



93 





Drawn 








into the 


Drawn 


Drawn 


Nature of Object. 


burrows, 
by or 


in, by or 
near the 


in, by or 
Bear the 




near the 


middle. 


base. 




apex. 






Petioles of a Clematis, somewhat 








pointed at the apex, and 
blunt at the base 


76 




24 


of the Ash, the thick basal 








end often drawn in to serve 








as food .... 


48-5 




51'5 


' of Eobinia, extremely thin, 








especially towards the apex, 








so as to be ill-fitted for 








plugging up the burrows . 


44 




56 


Triangles of paper, of the two sizes . 


62 


15 


23 


s^F 4-"U 11 svns* 1 


59 


25 


16 




65 


14 


21 





If we consider these several cases, we can 
hardly escape from the conclusion that worms 
show some degree of intelligence in their 
manner of plugging up their burrows. Each 
particular object is seized in too uniform a 
manner, and from causes which we can 
generally understand, for the result to be 
attributed to mere chance. That every object 
has not been drawn in by its pointed end, 
may be accounted for by labour having been 
saved through some being inserted by their 
broader or thicker ends. No doubt worms 



94: HABITS OP WORMS. CHAP. IL 

are led by instinct to plug up their burrows ; 
and it might have been expected that they 
would have been led by instinct how best 
to act in each particular case, independently 
of intelligence. We see how difficult it is to 
judge whether intelligence comes into play, 
for even plants might sometimes be thought 
to be thus directed; for instance when dis- 
placed leaves re-direct their upper surfaces 
towards the light by extremely complicated 
movements and by the shortest course. With 
animals, actions appearing due to intelligence 
may be performed through inherited habit 
without any intelligence, although aborigin- 
ally thus acquired. Or the habit may have 
been acquired through the preservation and 
inheritance of beneficial variations of some 
other habit ; and in this case the new habit 
will have been acquired independently of 
intelligence throughout the whole course 
of its development. There is no a priori 
improbability in worms having acquired 
special instincts through either of these two 
latter means. Nevertheless it is incredible 
that instincts should have been developed 
in reference to objects, such as the leaves of 



CHAP. II. THEIR INTELLIGENCE. 95 

petioles of foreign plants, wholly unknown 
to the progenitors of the worms which act 
in the described manner. Nor are their actions 
so unvarying or inevitable as are most true 
instincts. 

As worms are not guided by special in- 
stincts in each particular case, though pos- 
sessing a general instinct to plug up their 
burrows, and as chance is excluded, the next 
most probable conclusion seems to be that 
they try in many different ways to draw in 
objects, and at last succeed in some one way. 
But it is surprising that an animal so low 
in the scale as a worm should have the 
capacity for acting in this manner, as many 
higher animals have no such capacity. For 
instance, ants may be seen vainly trying 
to drag an object transversely to their 
course, which could be easily drawn longi- 
tudinally; though after a time they gener- 
ally act in a wiser manner. M. Fabre 
states* that a Sphex an insect belong- 
ing to the same highly-endowed order 
with ants stocks its nest with paralysed 

* See his interesting work, ' Souvenirs entomologiques,' 1879 
pp. 168-177. 



96 HABITS OF WORMS. CHAP. II. 

grasshoppers, which are invariably dragged 
into the burrow by their antennae. When 
these were cut off close to the head, the 
Sphex seized the palpi ; but when these 
were likewise cut off, the attempt to drag 
its prey into the burrow was given up in 
despair. The Sphex had not intelligence 
enough to seize one of the six legs or 
the ovipositor of the grasshopper, which, as 
M. Fabre remarks, would have served equally 
well. So again, if the paralysed prey with 
an egg attached to it be taken out of the 
cell, the Sphex after entering and finding the 
cell empty, nevertheless closes it up in the 
usual elaborate manner. Bees will try to 
escape and go on buzzing for hours on a 
window, one half of which has been left open. 
Even a pike continued during three months 
to dash and bruise itself against the glass 
sides of an aquarium, in the vain attempt to 
seize minnows on the opposite side.* A cobra- 
snake was seen by Mr. Layard f to act much 
more wisely than either the pike or the Sphex ; 

* Mobius, ' Die Bewegungen der Thiere,' &c., 1873, p. 111. 
t ' Annals and Mag. of N. History,' series ii. voL ix. 1852 
p. 333. 



HAP. II. THEIR INTELLIGENCE. 97 

it had swallowed a toad lying within a hole, 
and could not withdraw its head ; the toad 
was disgorged, and began to crawl away ; it 
was again swallowed and again disgorged; 
and now the snake had learnt by experience, 
for it seized the toad by one of its legs and 
drew it out of the hole. The instincts of 
even the higher animals are often followed 
in a senseless or purposeless manner : the 
weaver-bird will perseveringly wind threads 
through the bars of its cage, as if building a 
nest : a squirrel will pat nuts on a wooden 
floor, as if he had just buried them in the 
ground : a beaver will cut up logs of wood and 
drag them about, though there is no water to 
dam up ; and so in many other cases. 

Mr. Romanes, who has specially studied 
the minds of animals, believes that we can 
safely infer intelligence, only when we see an 
individual profiting by its own experience. 
By this test the cobra showed some intelli- 
gence ; but this would have been much 
plainer if on a second occasion he had drawn 
a toad out of a hole by its leg. The Sphex 
failed signally in this respect. Now if 
worms try to drag objects into their burrows 



98 HABITS OF WORMS. CHAP. II. 

first in one way and then in another, until 
they at last succeed, they profit, at least in 
each particular instance, by experience. 

But evidence has been advanced showing 
that worms do not habitually try to draw 
objects into their burrows in many different 
ways. Thus half-decayed lime-leaves from 
their flexibility could have been drawn in by 
their middle or basal parts, and were thus 
drawn into the burrows in considerable 
numbers; yet a large majority were drawn 
in by or near the apex. The petioles of the 
Clematis could certainly have been drawn in 
with equal ease by the base and apex ; yet 
threetimes and in certain cases five times as 
many were drawn in by the apex as by the 
base. It might have been thought that the 
loot-stalks of leaves would have tempted the 
worms as a convenient handle ; yet they are- 
not largely used, except when the base of the 
blade is narrower than the apex. A large 
number of the petioles of the ash are drawn 
in by the base ; but this part serves the 
worms as food. In the case of pine-leaves 
worms plainly show that they at least do 
not seize the leaf by chance ; but their 



CHAP. II. THEIR INTELLIGENCE. 99 

choice does not appear to be determined by 
the divergence of the two needles, and the 
consequent advantage or necessity of drawing 
them into their burrows by the base. With 
respect to the triangles of paper, those which 
had been drawn in by the apex rarely had 
their bases creased or dirty ; and this shows 
that the worms had not often first tried to 
drag them in by this end. 

If worms are able to judge, either before 
drawing or after having drawn an object 
close to the mouths of their burrows, how 
best to drag it in, they must acquire some 
notion of its general shape. This they pro- 
bably acquire by touching it in many places 
with the anterior extremity of their bodies, 
which serves as a tactile organ. It may be 
well to remember how perfect the sense of 
touch becomes in a man when born blind and 
deaf, as are worms. If worms have the 
power of acquiring some notion, however 
rude, of the shape of an object and of their 
burrows, as seems to be the case, they deserve 
to be called intelligent ; for they then act in 
nearly the same manner as would a man 
under similar circumstances. 



.100 HABITS OP WORMS. CHAP. II. 

To sum up, as chance does not determine 
the manner in which objects are drawn into 
the burrows, and as the existence of special- 
ized instincts for each particular case cannot 
be admitted, the first and most natural sup- 
position is that worms try all methods until 
they at last succeed ; but many appearances 
are opposed to such a supposition. One 
alternative alone is left, namely, that worms, 
although standing low in the scale of organiz- 
ation, possess some degree of intelligence. 
This will strike every one as very impro- 
bable ; but it may be doubted whether we 
know enough about the nervous system of 
the lower animals to justify our natural dis- 
trust of such a conclusion. With respect to 
the small size of the cerebral ganglia, we 
should remember what a mass of inherited 
knowledge, with some power of adapting 
means to an end, is crowded into the minute 
brain of a worker-ant. 

Means by which icorms excavate their 
burrows. This is effected in two ways ; by 
pushing away the earth on all sides, and by 
swallowing it. In the former case, the worm 
inserts the stretched out and attenuated 



CHAP. II. EXCAVATION OF THEIR BURROWS. 101 

anterior extremity of its body into any little 
crevice, or hole; and then, as Perrier re- 
marks,* the pharynx is pushed forwards into 
this part, which consequently swells and 
pushes away the earth on all sides. The 
anterior extremity thus serves as a wedge. 
It also serves, as we have before seen, for 
prehension and suction, and as a tactile organ. 
A worm was placed on loose mould, and it 
buried itself in between two and three 
minutes. On another occasion four worms 
disappeared in 1 5 minutes between the sides 
of the pot and the earth, which had been 
moderately pressed down. On a third oc- 
casion three large worms and a small one 
were placed on loose mould well mixed with 
fine sand and firmly pressed down, and they 
all disappeared, except the tail of one, in 
3.5 minutes. On a fourth occasion six large 
worms were placed on argillaceous mud 
mixed with sand firmly pressed down, and 
they disappeared, except the extreme tips of 
the tails of two of them, in 40 minutes. In 
none of these cases, did the worms swallow, 
as far as could be seen, any earth. They 

* ' Archives de Zoolog. exper.' torn. iii. 1874, p. 405. 

l 2 



102 HABITS OF WORMS. CHAP. II 

generally entered the ground close to the 
sides of the pot 

A pot was next filled with very fine ferru- 
ginous sand, which was pressed down, well 
watered, and thus rendered extremely com- 
pact. A large worm left on the surface did 
not succeed in penetrating it for some hours, 
and did not bury itself completely until 25 
hrs. 40 min. had elapsed. This was effected 
by the sand being swallowed, as was evident 
by the large quantity ejected from the vent y 
long before the whole body had disappeared. 
Castings of a similar nature continued to lie 
ejected from the burrow during the whole 
of the following day 

As doubts have been expressed by some 
writers whether worms ever swallow earth 
solely for the sake of making their burrows, 
some additional cases may be given. A mass 
of fine reddish sand, 23 inches in thickness, 
left on the ground for nearly two years, 
had been penetrated in many places by 
worms ; and their castings consisted partly of 
the reddish sand and partly of black earth 
brought up from beneath the mass. This 
sand had been dug up from a considerable 



CHAP. II. EXCAVATION OF THEIR BURROWS. 103 

depth, and was 01 so poor a nature that 
weeds could not grow on it. It is therefore 
highly improbable that it should have been 
swallowed by the worms as food. Again in 
u field near my house the castings frequently 
consist of almost pure chalk, which lies at only 
a, little depth beneath the surface ; and here 
again it is very improbable that the chalk 
should have been swallowed for the sake of 
the very little organic matter which could 
have percolated into it from the poor over- 
lying pasture. Lastly, a casting thrown up 
through the concrete and decayed mortar 
between the tiles, with which the now ruined 
aisle of Beaulieu Abbey had formerly been 
paved, was washed, so that the coarser 
matter alone was left. This consisted of 
grains of quartz, micaceous slate, other rocks, 
and bricks or tiles, many of them from -^ to 
T\J- inch in diameter. No one will suppose 
that these grains were swallowed as food, yet 
they formed more than half of the casting, 
for they weighed 19 grains, the whole cast- 
ing having weighed 33 grains. Whenever a 
worm burrows to a depth of some feet in 
undisturbed compact ground, it must form its 



104 HABITS OF WORMS. CHAP. II.. 

passage by swallowing the earth ; for it is 
incredible that the ground could yield on all 
sides to the pressure of the pharynx when 
pushed forwards within the worm's body. 

That worms swallow a larger quantity of 
earth for the sake of extracting any nutritious 
matter which it may contain than for making 
their burrows, appears to me certain. But 
as this old belief has been doubted by so high 
an authority as Claparede, evidence in its 
favour must be given in some detail. There 
is no a priori improbability in such a belief, 
for besides other annelids, especially the 
Arenicola marina, which throws up such a 
profusion of castings on our tidal sands, and 
which it is believed thus subsists, there are 
animals belonging to the most distinct classes, 
which do not burrow, but habitually swallow 
large quantities of sand ; namely, the mollus- 
can Onchidium and many Echinoderms.* 

If earth were swallowed only when worms 
deepened their burrows or made new ones, 
castings would be thrown up only occasion- 
ally ; but in many places fresh castings may 

* I state this on the authority of Semper, "Reisen iiu 
Archipel der Philippinen," Th. ii. 1877. p. 30. 






CIIAP. II. EARTH SWALLOWED AS FOOD. 105 

be seen every morning, and the amount of 
earth ejected from the same burrow on succes- 
sive days is large. Yet worms do not burrow 
to a great depth, except when the weather 
is very dry or intensely cold. On my lawn 
the black vegetable mould or humus is only 
about 5 inches in thickness, and overlies light- 
coloured or reddish clayey soil: now when 
castings are thrown up in the greatest 
profusion, only a small proportion are light 
coloured, and it is incredible that the worms 
should daily make fresh burrows in every 
direction in the thin superficial layer of 
dark -coloured mould, unless they obtained 
nutriment of some kind from it. I have ob- 
served a strictly analogous case in a field near 
my house where bright red clay lay close 
beneath the surface. Again on one part of 
the Downs near Winchester the vegetable 
mould overlying the chalk was found to be 
only from 3 to 4 inches in thickness ; and the 
many castings here ejected were as black as 
ink and did not effervesce with acids ; so that 
the worms must have confined themselves to 
this thin superficial layer of mould, of which 
large quantities were daily swallowed. In 



106 HABITS OF WORMS. CHAP. II. 

another place at no great distance the cast- 
ings were white ; and why the worms should 
have burrowed into the chalk in some places 
and not in others, I am unable to conjecture. 

Two great piles of leaves had been left to 
decay in my grounds, and months after their 
removal, the bare surface, several yards in 
diameter, was so thickly covered during 
several months with castings that they formed 
an almost continuous layer; and the large 
number of worms which lived here must have 
subsisted during these months on nutritious 
matter contained in the black earth. 

The lowest layer from another pile of de- 
cayed leaves mixed with some earth was ex- 
amined under a high power, and the number 
of spores of various shapes arid sizes which 
it contained was astonishingly great; and 
these crushed in the gizzards of worms may 
largely aid in supporting them. When- 
ever castings are thrown up in the greatest 
number, few or no leaves are drawn into the 
burrows ; for instance the turf along a hedge- 
row, about 200 yards in length, was daily 
observed in the autumn during several weeks, 
and every morning many fresh castings were 



CHAP. II EAETH SWALLOWED AS FOOD. 107 

seen ; but not a single leaf was drawn into these 
burrows. These castings from their blackness 
and from the nature of the subsoil could not 
have been brought up from a greater depth 
than 6 or 8 inches. On what could these 
worms have subsisted during this whole time, 
if not on matter contained in the black earth ? 
On the other hand, whenever a large number 
of leaves are drawn into the burrows, the 
worms seem to subsist chiefly on them, for 
few earth-castings are then ejected on the 
surface. This difference in the behaviour of 
worms at different times, perhaps explains a 
statement by Claparede, namely, that triturated 
leaves and earth are always found in distinct 
parts of their intestines. 

Worms sometimes abound in places where 
they can rarely or never obtain dead or 
living leaves ; for instance, beneath the pave- 
ment in well-swept courtyards, into which 
leaves are only occasionally blown. My son 
Horace examined a house, one corner of 
which had subsided; and he found here in 
the cellar, which was extremely damp, many 
small worm-castings thrown up between the 
stones with which the cellar was paved ; and 



108 HABITS OF WORMS. CHAP. 1L 

in this case it is improbable that the worms 
could ever have obtained leaves. Mr. A. C. 
Horner confirms this account, as he has seen 
castings in the cellars of his house, which is 
an old one, at Tonbridge. 

But the best evidence, known to me, of 
worms subsisting for at least considerable 
periods of time solely on the organic matter 
contained in earth, is afforded by some facts 
communicated to me by Dr. King. Near 
Nice large castings abound in extraordinary 
numbers, so that 5 or were often found 
within the space of a square foot. They 
consist of fine, pale-coloured earth, containing 
calcareous matter, which after having passed 
through the bodies of worms and being dried, 
coheres with considerable force. I have 
reason to believe that these castings had been 
formed by species of Perichseta, which have 
been naturalised here from the East.* They 

* Dr. King gave me some worms collected near Nice, which,, 
as he "believes, had constructed these castings. They were sent 
to M. Perrier, who with great kindness examined and named them 
for me : they consisted of Perichceta affinis, a native of Cochin 
China and of the Philippines ; P. Luzonica, a native of Luzon 
in the Philippines ; and P. JJoulleti, which lives near Calcutta. 
M. Perrier informs me that species of Perichajta have heen natural- 
ised in the gardens near Montpellier and in Algiers. Before I 



CHAP. II. EARTH SWALLOV.'ED AS FOOD. 



109 



rise like towers (see Fig. 2), with their sum- 
mits often a little broader than their bases,, 




Fig. 2. 

Tower-like casting from near Nice, constructed ot earth, voided 
probably by a species of Perichjeta : of natural size, copied from 
a photograph. 

retimes to a height of above 3 and often 

had any reason to suspect that the tower-like castings from Nice 
had been formed by worms not endemic in the country, I was 
greatly surprised to see how closely they resembled castings sent 
to me from near Calcutta, where it is known that species of 
Perichjeta abound. 



110 HABITS OF WORMS. CHAP. II. 

to a height of 2^ inches. The tallest of those 
which were measured was 3*3 inches in height 
and 1 inch in diameter. A small cylindrical 
passage runs up the centre of each tower, 
through which the worm ascends to eject the 
earth which it has swallowed, and thus to 
add to its height. A structure of this kind 
would not allow leaves being easily dragged 
from the surrounding ground into the bur- 
rows ; and Dr. King, who looked carefully, 
never saw even a fragment of a leaf thus 
drawn in. Nor could any trace be discovered 
of the worms having crawled down the ex- 
terior surfaces of the towers in search of 
leaves; and had they done so, tracks would 
almost certainly have been left on the upper 
part whilst it remained soft. It does not, 
however, follow that these worms do not 
draw leaves into their burrows during some 
other season of the year, at which time they 
would not build up their towers. 

From the several foregoing cases, it can 
hardly be doubted that worms swallow earth, 
not only for the sake of making their bur- 
rows, but for obtaining food. Hensen, how- 
ever, concludes from his analyses of mould 






CHAP. II. DEPTH OF THEIR BURROWS. Ill 

that worms probably could not live on. 
ordinary vegetable mould, though he admits 
that they might be nourished to some extent 
by leaf-mould.* But we have seen that 
worms eagerly devour raw meat, fat, and 
dead worms ; and ordinary mould can hardly 
fail to contain many ova, larvae, and small 
living or dead creatures, spores of crypto- 
gamic plants, and microcoeci, such as those 
which give rise to saltpetre. These various 
organisms, together with some cellulose from 
any leaves and roots not utterly decayed, 
might well account for such large quantities 
of mould being swallowed by worms. It 
may be worth while here to recall the fact 
that certain species of Utricularia, which grow 
in damp places in the tropics, possess bladders 
beautifully constructed for catching minute 
subterranean animals ; and these traps would 
not have been developed unless many small 
animals inhabited such soil. 

The depth to which worms penetrate, and 
the construction of their burrows. Although 
worms usually live near the surface, yet they 

* 'Zeitschrift fur wissenschaft. Zoolog.' B. xxviii. 1877, 
p. 364. 



112 HABITS OF WORMS. CHAP. II. 

burrow to a considerable depth during long- 
continued dry weather and severe cold. In 
Scandinavia, according to Eisen, and in Scot- 
land, according to Mr. Lindsay Carnagie, the 
burrows run down to a depth of from 7 to 8 
feet ; in North Germany, according to Hoff- 
meister, from 6 to 8 feet, but Hensen says, 
from 3 to 6 feet. This latter observer has seen 
worms frozen at a depth of 1^ feet beneath 
the surface. I have not myself had many 
opportunities for observation, but I have often 
met with worms at depths of 3 to 4 feet. 
In a bed of fine sand overlying the chalk, 
which had never been disturbed, a worm was 
cut into two at 55 inches, and another was 
found here at Down in December at the bottom 
of its burrow, at 61 inches beneath the surface. 
Lastly, in earth near an old Roman Villa, 
which had not been disturbed for many centu- 
ries, a worm was met with at a depth of 66 
inches ; and this was in the middle of August. 
The burrows run down perpendicularly, or 
more commonly a little obliquely. They are 
said sometimes to branch, but as far as I have 
seen this does not occur, except in recently 
dug ground and near the surface. They are 



CHAP. II. CONSTRUCTION OF THEIR BURROWS. 113 

generally, or as I believe invariably, lined 
with a thin layer of fine, dark-coloured earth 
voided by the worms ; so that they must 
at first be made a little wider than their 
ultimate diameter. I have seen several 
burrows in undisturbed sand thus lined at 
a depth of 4 ft. 6 in. ; and others close 
to the surface thus lined in recently dug 
ground. The walls of fresh burrows are 
often dotted with little globular pellets of 
voided earth, still soft and viscid ; and these, 
as it appears, are spread out on all sides by 
the worm as it travels up or down its burrow. 
The lining thus formed becomes very com- 
pact and smooth when nearly dry, and 
closely fits the worm's body. The minute 
reflexed bristles which project in rows on 
all sides from the body, thus have excellent 
points of support ; and the burrow is rendered 
well adapted for the rapid movement of the 
animal. The lining appears also to strengthen 
the walls, and perhaps saves the worm's body 
from being scratched. I think so because 
several burrows which passed through a layer 
of sifted coal-cinders, spread over turf to a 
thickness of 1 J inch, had been thus lined to an 



114 HABITS OF WORMS. CHAP. If. 

unusual thickness. In this case tne worms, 
judging from the castings, had pushed the 
cinders away on all sides and had not 
swallowed any of them. In another place, 
burrows similarly lined, passed through a 
layer of coarse coal-cinders, 3| inches in 
thickness. We thus see that the burrows are 
not mere excavations, but may rather be 
compared with tunnels lined with cement. 

The mouths of the burrow are in addition 
often lined with leaves ; and this is an instinct 
distinct from that of plugging them up, and 
does not appear to have been hitherto noticed. 
Many leaves of the Scotch-fir or pine (Pinus 
sylvestris) were given to worms kept in con- 
finement in two pots ; and when after several 
weeks the earth was carefully broken up, the 
upper parts of three oblique burrows were 
found surrounded for lengths of 7, 4, and 
3J inches with pine-leaves, together with 
fragments of other leaves which had been 
given the worms as food. Glass beads and 
bits of tile, which had been strewed on the 
surface of the soil, were stuck into the inter- 
stices between the pine-leaves ; and these 
interstices were likewise plastered with the 



CHAP. II. CONSTRUCTION OF THEIR BURROWS. 115 

viscid castings voided by the worms. The 
structures thus formed cohered so well, that I 
succeeded in removing one with only a little 
earth adhering to it. It consisted of a slightly 
curved cylindrical case, the interior of which 
could be seen through holes in the sides and 
at either end. The pine-leaves had all been 
drawn in by their bases ; and the sharp points 
of the needles had been pressed into the 
lining of voided earth. Had this not been 
effectually done, the sharp points would have 
prevented the retreat of the worms into their 
burrows ; and these structures would have 
resembled traps armed with converging 
points of wire, rendering the ingress of an 
.animal easy and its egress difficult or inr 
possible. The skill shown by these worms 
is noteworthy and is the more remarkable, as 
the Scotch pine is not a native of this district. 
After having examined these burrows 
made by worms in confinement, I looked at 
those in a flower-bed near some Scotch pines. 
These had all been plugged up in the ordinary 
manner with the leaves of this tree, drawn in 
for a length of from 1 to 1^ inch; but the 
mouths of many of them were likewise lined 

K 



116 HABITS OF WORMS. CHAP. II. 

with them, mingled with fragments of other 
kinds of leaves, drawn in to a depth of 4 or 5 
inches. Worms often remain, as formerly 
stated, for a long time close to the mouths 
of their burrows, apparently for warmth ; 
and the basket-like structures formed of 
leaves would keep their bodies from corning 
into close contact with the cold damp earth. 
That they habitually rested on the pine-leaves, 
was rendered probable by their clean and 
almost polished surfaces. 

The burrows which run far down into the 
ground, generally, or at least often, terminate 
in a little enlargement or chamber. Here, ac- 
cording to Hoifmeister, one or several worms 
pass the winter rolled up into a ball. Mr. 
Lindsay Carnagie informed me (1838) that 
he had examined many burrows over a stone- 
quarry in Scotland, where the overlying 
boulder-clay and mould had recently been 
cleared away, and a little vertical cliff thus 
left. In several cases the same burrow was a 
little enlarged at two or three points one 
beneath the other ; and all the burrows ter- 
minated in a rather large chamber, at a depth 
of 7 or 8 feet from the surface. These chain- 



CHAP. II. CONSTRUCTION OF THEIR BURROWS. 117 

bers contained many small sharp bits of stone 
and husks of flax-seeds. They must also 
have contained living seeds, for on the follow- 
ing spring Mr. Carnagie saw grass-plants 
sprouting out of some of the intersected 
chambers. I found at Abinger in Surrey 
two burrows terminating in similar chambers 
at a depth of 36 and 41 inches, and these 
were lined or paved with little pebbles, 
about as large as mustard seeds ; and in 
one of the chambers there was a decayed 
oat-grain, with its husk. Hensen likewise 
states that the bottoms of the burrows are 
lined with little stones ; and where these 
could not be procured, seeds, apparently of 
the pear, had been used, as many as fifteen 
having been carried down into a single 
burrow, one of which had germinated.* We 
thus see how easily a botanist might be 
deceived who wished to learn how long 
deeply buried seeds remained alive, if he 
were to collect earth from a considerable 
depth, on the supposition that it could 
contain only seeds which had long lain 
buried. It is. probable that the little stones, 

* ' Zeitscbrift fur wissenschaft. Zoolog.' B. xxviii. 1877, p. 356 

K 2 



"118 HABITS OF WORMS. CHAP. II. 

.as well as the seeds, are carried down from 
the surface by being swallowed ; for a sur- 
prising number of glass beads, bits of tile 
and of glass were certainly thus carried down 
'by worms kept in pots ; but some may have 
been carried down within their mouths. The 
tsole conjecture which I can form why worms 
line their winter-quarters with little stones 
;and seeds, is to prevent their closely coiled-up 
foodies from coming into close contact with 
"the surrounding cold soil ; and such contact 
would perhaps interfere with their respiration 
which is effected by the skin alone. 

A worm after swallowing earth, whether 
for making its burrow or for food, soon comes 
to the surface to empty its body. The ejected 
earth is thoroughly mingled with the intestinal 
secretions, and is thus rendered viscid. After 
being dried it sets hard. I have watched 
worms during the act of ejection, and when 
the earth was in a very liquid state it was 
ejected in little spurts, and by a slow peri- 
staltic movement when not so liquid. It is 
not cast indifferently on any side, but with 
some care, first on one and then on another 
side ; the tail being used almost like a trowel. 



CHAP. II. EJECTION OF THEIR CASTINGS. 119' 

When a worm comes to the surface to eject 
earth, the tail protrudes, but when it collects- 
leaves its head must protrude. Worms there- 
fore must have the power of turning round! 
ill their closely-fitting burrows ; and this, as- 
it appears to us, would be a difficult feat. As 
soon as a little heap has been formed, the- 
worm apparently avoids, for the sake of 
safety, protruding its tail ; and the earthy 
matter is forced up through the previously 
deposited soft mass. The mouth of the same- 
burrow is used for this purpose for a consider- 
able time. In the case of the tower-like 
castings (see Fig. 2) near Nice, and of the- 
similar but still taller towers from Bengal 
(hereafter to be described and figured), a 
considerable degree of skill is exhibited in 
their construction. Dr. King also observed 
that the passage up these towers hardly ever 
ran in the same exact line with the under- 
lying burrow, so that a thin cylindrical object 
such as a haulm of grass, could not be 
passed down the tower into the burrow ; and 
this change of direction probably serves in 
some manner as a protection. 

Worms do not always eject their castings on 



120 HABITS OF WORMS. CHAP. II. 

the surface of the ground. When they can 
find any cavity, as when burrowing in newly 
turned-up earth, or between the stems of 
banked-up plants, they deposit their castings 
in such places. So again any hollow beneath 
a large stone lying on the surface of the 
ground, is soon filled up with their castings. 
According to Hensen, old burrows are habitu- 
ally used for this purpose ; but as far as iny 
experience serves, this is not the case, except- 
ing with those near the surface in recently dug 
ground. I think that Hensen may have been 
deceived by the walls of old burrows, lined 
with black earth, having sunk in or collapsed ; 
for black streaks are thus left, and these are 
conspicuous when passing through light- 
coloured soil, and might be mistaken for 
completely filled-up burrows. 

It is certain that old burrows collapse in 
the course of time ; for as we shall see in the 
next chapter, the fine earth voided by worms, 
if spread out uniformly, would form in many 
places in the course of a year a layer -J- of an 
inch in thickness; so that at any rate this large 
amount is not deposited within the old unused 
burrows. If the burrows did not collapse, 



CHAP. II. THE COLLAPSE OF OLD BURROWS. 121 

tlie whole ground would be first thickly 
riddled with holes to a depth of ahout ten 
inches, and in fifty years a hollow unsup- 
ported space, ten inches in depth, would be 
left. The holes left by the decay of succes- 
sively formed roots of trees and plants must 
likewise collapse in the course of time. 

The burrows of worms run down perpen- 
dicularly or a little obliquely, and where the 
soil is at all argillaceous, there is no difficulty 
in believing that the walls would slowly flow 
or slide inwards during very wet weather. 
When, however, the soil is sandy or 
mingled with many small stones, it can 
hardly be viscous enough to flow .inwards 
during even the wettest weather; but another 
agency may here come into play. After 
much rain the ground swells, and as it cannot 
expand laterally, the surface rises ; during dry 
weather it sinks again. For instance, a large 
flat stone laid on the surface of a field sank 
3*33 mm. whilst the weather was dry between 
May 9th and June 13th, and rose 1*91 mm. 
between September 7th and 19th of the same 
year, much rain having fallen during the latter 
part of this time. During frosts and thaws 



122 HABITS OF WORMS. CHAP. II. 

the movements were twice as great. These 
observations were made by my son Horace, 
who will hereafter publish an account of the 
movements of this stone during successive 
wet and dry seasons, and of the effects of its 
being undermined by worms. Now when 
the ground swells, if it be penetrated by 
cylindrical holes, such as worm-burrows, 
their walls will tend to yield and be pressed 
inwards ; and the yielding will be greater 
in the deeper parts (supposing the whole 
to be equally moistened) from the greater 
weight of the superincumbent soil which has 
to be raised, than in the parts near the sur- 
face. When the ground dries, the walls will 
shrink a little and the burrows will be a 
little enlarged. Their enlargement, however, 
through the lateral contraction of the 
ground, will not be favoured, but rather op- 
posed, by the weight of the superincumbent 
soil. 

Distribution of Worms. Earth-worms are 
found in all parts of the world, and some of 
the genera have an enormous range.* They 
inhabit the most isolated islands ; they 

* Pcrrier, ' Archives de Zoolog. exper.' torn. 3, p. 378, 1874. 



CHAP. II THEIR WIDE DISTRIBUTION. 123 

abound in Iceland, and are known to exist 
in the West Indies, St. Helena, Madagascar, 
New Caledonia and Tahiti. In the Antarctic 
regions, worms from Kerguelen Land have 
been described by Ray Lankester; and I 
found them in the Falkland Islands. How 
they reach such isolated islands is at present 
quite unknown. They are easily killed by 
salt-water, and it does not appear probable 
that young worms or their egg-capsules could 
be carried in earth adhering to the feet or 
beaks of land-birds. Moreover Kerguelen 
Land is not now inhabited by any land-bird. 

In this volume we arc chiefly concerned with 
the earth cast up by worms, and I have gleaned 
a few facts on this subject with respect to 
distant lands. Worms throw up plenty of 
castings in the United States. In Venezuela, 
castings, probably ejected by species of 
Urochaeta, are common in the gardens and 
fields, but not in the forests, as I hear from 
Dr. Ernst of Caracas. He collected 156 
castings from the court-yard of his house, 
having an area of 200 square yards. They 
varied in bulk from half a cubic centimeter to 
five cubic centimeters, and were on an average 



124. HABITS OF WORMS. CHAP. II. 

three cubic centimeters. They were, therefore, 
-of small size in comparison with those often 
found in England ; for six large castings from 
a field near my house averaged 1 6 cubic centi- 
meters. Several species of earth-worms are 
common in St. Catharina in South Brazil, and 
Fritz Miiller informs me " that in most parts of 
" the forests and pasture-lands, the whole soil, 
" to a depth of a quarter of a metre, looks as if it 
" had passed repeatedly through the intestines 
" of earth-worms, even where hardly any cast- 
4i ings are to be seen on the surface." A 
gigantic but very rare species is found there, 
the burrows of which are sometimes even two 
centimeters or nearly % of an inch in diameter, 
and which apparently penetrate the ground 
to a great depth. 

In the dry climate of New South Wales, I 
hardly expected that worms would be com- 
mon ; but Dr. Gr. Krefft of Sydney, to whom 
I applied, after making enquiries from 
gardeners and others, and from his own 
observations, informs me that their castings 
abound. He sent me some collected after 
heavy rain, and they consisted of little pellets, 
about '15 inch in diameter ; and the blackened 



CHAP. II. THEIR WIDE DISTRIBUTION. 125 

:sandy earth of which they were formed still 
cohered with considerable tenacity. 

The late Mr. John Scott of the Botanic 
Gardens near Calcutta made many observa- 
tions for me 011 worms living under the hot 
;and humid climate of Bengal. The castings 
abound almost everywhere, in jungles and in 
the open ground, to a greater degree, as he 
thinks, than in England. After the water 
has subsided from the flooded rice-fields, the 
whole surface very soon becomes studded with 
castings a fact which much surprised Mr, 
:Scott, as he did not know how long worms 
could survive beneath water. They cause 
much trouble in the Botanic garden, "for 
'" some of the finest of our lawns can be kept 
" in anything like order only by being almost 
" daily rolled ; if left undisturbed for a few days 
** they become studded with large castings." 
These closely resemble those described as 
abounding near Nice ; and they are probably 
the work of a species of Perichasta. They 
.stand up like towers, with an open passage in 
the centre. 

A figure of one of these castings from a 
photograph is here given (Fig. 3). The 



126 



HABITS OF WORMS. 



CIIAP. IE. 



largest received by me was 3^ inches in 
height and 1*35 inch in diameter ; another 




Fig. 3. 

A tower-like casting, probably ejected by a species of Perichasta 
from the Botanic Garden, Calcutta : of natural size, engraved 
from a photograph 

was only | inch in diameter and 2| in height. 



CHAP. II. THEIR WIDE DISTRIBUTION. 127 

In the following year, Mr. Scott measured 
several of the largest ; one was inches in 
height and nearly 1J in diameter : two others 
were 5 inches in height and respectively 2 
and rather more than 2J inches in diameter. 
The average weight of the 22 castings sent to 
me was 35 grammes (li oz.) ; and one of them 
weighed 44*8. grammes (or 2 oz.). All these 
eastings were thrown up either in one night 
or in two. Where the ground in Bengal is 
dry, as under large trees, castings of a different 
kind are found in vast numbers : these con- 
sist of little oval or conical bodies, from about 
the gV to rather above -^ of an inch in 
length. They are obviously voided by a 
distinct species of worms. 

The period during which worms near 
Calcutta , display such extraordinary activity 
lasts for only a little over two months, 
namely, during the cool season after the rains. 
At this time they are generally found within 
about 10 inches beneath the surface. During 
the hot season they burrow to a greater depth, 
and are then found coiled up and apparently 
hybernating. Mr. Scott has never seen them 
at a greater depth than 2J feet, but has heard 



128 HABITS OF WORMS. CHAP. IT. 

of their having been found at 4 feet. Within 
the forests, fresh castings may he found even 
during the hot season. The worms in the 
Botanic garden, during the cool and dry 
season, draw many leaves and little sticks 
into the mouths of their burrows, like our 
English worms; but they rarely act in this 
manner during the rainy season. 

Mr. Scott saw worm-castings on the lofty 
mountains of Sikkim in Xorth India. In 
South India Dr. King found in one 
place, on the plateau of the Nilgiris, at an 
elevation of 7000 feet, " a good many 
castings," which are interesting for their 
great size. The worms which eject them are- 
seen only during the wet season, and are- 
reported to be from 12 to 15 inches in length, 
and as thick as a man's little finger. These- 
castings were collected by Dr. King after 
a period of 110 days without any rain; and 
they must have been ejected either during 
the north-east or more probably during 
the previous south-west monsoon ; for their 
surfaces had suffered some disintegration and 
they were penetrated by many fine roots. A 
drawing is here given (Fig. 4) of one which 



CHAP. II. THEIR WIDE DISTRIBUTION. 129" 

seems to have best retained its original size 
and appearance. Notwithstanding some loss 
from disintegration, five of the largest of these 
castings (after having been well sun-dried) 
weighed each on an average 89-5 grammes,. 







Fig. 4. 

A casting from the Nilgiri Mountains in South India ; of 
natural size, engraved from a photograph. 



or above 3 oz. ; and the largest weighed 
123-14 grammes, or 4^- oz., that is, above a. 
quarter of a pound ! The largest convolutions 
were rather more than one inch in diameter ; 
but it is probable that they had subsided a little 



130 HABITS OF WORMS. CHAP. II. 

whilst soft, and that their diameters had thus 
been increased. Some had flowed so much 
that they now consisted of a pile of almost flat 
confluent cakes. All were formed of fine, 
rather light-coloured earth, and were surpris- 
ingly hard and compact, owing no doubt to 
the animal matter by which the particles of 
earth had been cemented together. They 
did not disintegrate, even when left for some 
hours in water. Although they had been 
cast up on the surface of gravelly soil, they 
contained extremely few bits of rock, the 
largest of which was only '15 inch in 
diameter. 

Dr. King saw in Ceylon a worm about 2 
feet in length and ^ inch in diameter ; and 
he was told that it was a very common species 
during the wet season. These worms must 
throw up castings at least as large as those on 
the Nilgiri Mountains; but Dr. King saw 
none during his short visit to Ceylon. Suffi- 
cient facts have now been given, showing 
that worms do much work in bringing up 
fine earth to the surface in most or all parts 
of the world, and under the most different 
climates. 



( 131 ) 



CHAPTER III. 

THE AMOUNT OF FIXE EARTH BROUGHT UP BY 
WORMS TO THE SURFACE. 

Rate at which various objects strewed on the surface of grass- 
fields are covered up by the castings of worms The burial of 
a paved path The slow subsidence of great stones left on the 
surface The number of worms which live within a given 
space The weight of earth ejected from a burrow, and from 
all the burrows within a given space The thickness of the 
layer of mould which the castings on a given space would 
form within a given time if uniformly spread out The slow 
rate at which mould can increase to a great thickness 
Conclusion. 

WE now come to the more immediate subject 
of this volume, namely, the amount of earth 
which is brought up by worms from beneath 
the surface, and is afterwards spread out more 
or less completely by the rain and wind. The 
amount can be judged of by two methods, - 
by the rate at which objects left on the 
surface are buried, and more accurately by 
weighing the quantity brought up within a 

L 



132 AMOUNT OF EAKTH CHAP. III. 

given time. We will begin with the first 
method, as it was first followed. 

Near Maer Hall in Staffordshire, quick-lime 
had been spread about the year 1827 thickly 
over a field of good pasture-land, which had 
not since been ploughed. Some square holes 
were dug in this field in the beginning of 
October 183*7 ; and the sections showed a 
layer of turf, formed by the matted roots of 
the grasses, J inch in thickness, beneath 
which, at a depth of 2J inches (or 3 inches 
from the surface), a layer of the lime in 
powder or in small lumps could be distinctly 
seen running all round the vertical sides of 
the holes. The soil beneath the layer of 
lime was either gravelly or of a coarse sandy 
nature, and differed considerably in appear- 
ance from the overlying dark-coloured fine 
mould. Coal-cinders had been spread over 
a part of this same field either in the year 
1833 or 1834; and when the above holes 
were dug, that is after an interval of 3 or 4 
years, the rinders formed a line of black spots 
round the holes, at a depth of 1 inch beneath 
the surface, parallel to and above the white 
layer of lime. Over another part of this field 



CHAP. III. BROUGHT UP BY WORMS. 133 

cinders had been strewed, only about half-a- 
year before, and these either still lay on the 
surface or were entangled among the roots of 
the grasses ; and I here saw the commence- 
ment of the burying process, for worm-cast- 
ings had been heaped on several of the 
smaller fragments. After an interval of 
4f years this field was re-examined, and now 
the two layers of lime and cinders were found 
almost everywhere at a greater depth than 
before by nearly 1 inch, we will say by f of 
an inch. Therefore mould to an average 
thickness of '22 of an inch had been annually 
brought up by the worms, and had been 
spread over the surface of this field. 

Coal-cinders had been strewed over another 
field, at a date which could not be positively 
ascertained, so thickly that they formed 
(October, 1837) a layer, 1 inch in thickness 
at a depth of about 3 inches from the surface. 
The layer was so continuous that the over- 
lying dark vegetable mould was connected 
with the sub-soil of red clay only by the roots 
of the grasses ; and when these were broken, 
the mould and the red clay fell apart. In a 
third field, on which coal-cinders and burnt 

L 2 



134 AMOUNT OF EARTH CHAP. III. 

marl had been strewed several times at un- 
known dates, holes were dug in 1842 ; and a 
layer of cinders could be traced at a depth 
of 3j| inches, beneath which at a depth of 
9J inches from the surface there was a line 
of cinders together .with burnt marl. On the 
sides of one hole there were two layers of 
cinders, at 2 and 3^ inches beneath the sur- 
face ; and below them at a depth in parts 
of 9J, and in other parts of 10 J inches there 
were fragments of burnt marl. In a fourth 
field two layers of lime, one above the other, 
could be distinctly traced, and beneath them 
a layer of cinders and burnt marl at a depth 
of from 10 to 12 inches below the surface. 

A piece of waste, swampy land was 
enclosed, drained, ploughed, harrowed and 
thickly covered in the year 1822 with burnt 
marl and cinders. It was sowed with grass 
seeds, and now supports a tolerably good but 
coarse pasture. Holes were dug in this field 
in 1837, or 15 years after its reclamation, 
and we see in the accompanying diagram 
(Fig. 5), reduced to half of the natural scale, 
that the turf was ^ inch thick, beneath which 
there was a layer of vegetable mould 2 J inches 



CHAP. III. BEOUQHT UP BY WOKMS. 



135 



thick. This layer did not contain fragments 
of any kind ; but beneath it there was a layer 
of mould, 1 J inch in thickness, full of fragments 




Fig. 5. 

Section, reduced to half the natural scale, of the vegetable mould 
in a field, drained and reclaimed fifteen years previously ; A, 
turf; B, vegetable mould without any stones; C, mould with 
fragments of burnt marl, coal-cinders and quartz pebbles; 
D, sub-soil of black, peaty sand with quartz pebbles. 

of burnt marl, conspicuous fro'm their red 
colour, one of which near the bottom was an 



.136 AMOUNT OF EARTH CHAP. III. 

inch in length ; and other fragments of coal- 
cinders together with a few white quartz 
pebbles. Beneath this layer and at a depth of 
4^ inches from the surface, the original black, 
peaty, sandy soil with a few quartz pebbles 
was encountered. Here therefore the frag- 
ments of burnt marl and cinders had been 
covered in the course of 15 years by a layer 
of fine vegetable mould, only 2J inches in 
thickness, excluding the turf. Six and a half 
years subsequently this field was re-examined, 
and the fragments were now found at from 
4 to 5 inches beneath the surface. So that 
in this interval of 6 years, about 1^ inch of 
mould had been added to the superficial layer. 
I am surprised that a greater quantity had 
not been brought up during the whole 21 J 
years, for in the closely underlying black, 
peaty soil there were many worms. It is, 
however, probable that formerly, whilst the 
land remained poor, worms were scanty ; and 
the mould would then have accumulated 
slowly. The average annual increase of thick- 
ness for the whole period is *19 of an inch. 

Two other cases are worth recording. In 
the spring of 1835, a field, which had 



CHAP. IIL BKOUGHT UP BY WOEMS. 137 

long existed as poor pasture and was so 
swampy that it trembled slightly when 
stamped on, was thickly covered with red 
sand so that the whole surface appeared at 
first bright red. When holes were dug in 
this field after an interval of about 2 J years, 
the sand formed a layer at a depth of f in. 
beneath the surface. In 1842 (i.e., 7 years 
after the sand had been laid on) fresh holes 
were dug, and now the red sand formed a 
distinct layer, 2 inches beneath the surface., 
or 1|- inch beneath the turf; so that on an 
average, '21 inch of mould had been annu- 
ally brought to the surface. Immediately 
beneath the layer of red sand, the original 
substratum of black sandy peat extended. 

A grass field, likewise not far from Maer 
Hall, had formerly been thickly covered with 
marl, and was then left for several years as 
pasture; it was afterwards ploughed. A 
friend had three trenches dug in this field 
28 years after the application of the marl,* 

* This case is given in a postscript to my paper in the 
' Transact. Geolog. Soc.' (Vol. v. p. 505), and contains a serious 
error, as in the account received I mistook the figure 30 for 80. 
The tenant, moreover, formerly said that he had marled the field 
thirty years before, but was now positive that this was done in 



138 AMOUNT OF EARTH CHAP. III. 

and a layer of the marl fragments could be 
traced at a depth, carefully measured, of 12 
inches in some parts, and of 14 inches in 
other parts. This difference in depth de- 
pended on the layer being horizontal, whilst 
the surface consisted of ridges and furrows 
from the field having been ploughed. The 
tenant assured me that it had never been 
turned up to a greater depth than from 6 to 8 
inches ; and as the fragments formed an un- 
broken horizontal layer from 12 to 14 inches 
beneath the surface, these must have been 
buried by the worms whilst the land was 
in pasture before it was ploughed, for other- 
wise they would have been indiscriminately 
scattered by the plough throughout the 
whole thickness of the soil. Four-and-a-half 
years afterwards I had three holes dug in 
this field, in which potatoes had been lately 
planted, and the layer of marl-fragments was 
now found 13 inches beneath the bottoms of 
the furrows, and therefore probably 15 inches 



1809, that is twenty-eight years before the first examination of 
the field by my friend. The error, as far as the figure 80 is 
concerned, was corrected in an article by me, in the * Gardeners' 
Chronicle,' 1844, p. 218. 



CHAP. III. BROUGHT UP BY WORMS. 139 

beneath the general level of the field. It 
should, however, be observed that the thick- 
ness of the blackish sandy soil, which had 
been thrown up by the worms above the marl- 
fragments in the course of 32 years, would 
have measured less than 15 inches, if the field 
had always remained as pasture, for the soil 
would in this case have been much more 
compact. The fragments of marl almost rested 
on an undisturbed sub-stratum of white sand 
with quartz pebbles ; and as this would be 
little attractive to worms, the mould would 
hereafter be very slowly increased by their 
action. 

"We will now give some cases of the action 
of worms, on land differing widely from 
the dry sandy or the swampy pastures just 
described. The chalk formation extends all 
round my house in Kent; and its surface, 
from having been exposed during an immense 
period to the dissolving action of rain-water, 
is extremely irregular, being abruptly fes- 
tooned and penetrated by many deep well- 
like cavities.* During the dissolution of the 

* These pits or pipes are still in process of formation. During 
the last forty years I have seen or heard of five cases, in which a 



140 AMOUNT OF EAETH CHAP. III. 

chalk, the insoluble matter, including a vast 
number of unrolled flints of all sizes, has 



circular space, several feet in diameter, suddenly fell in, leaving 
on the field an open hole with perpendicular sides, some feet in 
depth. This occurred in one of my own fields, whilst it was 
being rolled, and the hinder quarters of the shaft horse fell in ; two 
or three cart-loads of rubbish were required to fill up the hole. 
The subsidence occurred where there was a broad depression, as 
if the surface had fallen in at several former periods. I heard 
of a hole which must have been suddenly formed at the bottom 
of a small shallow pool, where sheep had been washed during 
many years, and into which a man thus occupied fell to his great 
terror. The rain-water over this whole district sinks perpen- 
dicularly into the ground, but the chalk is more porous in certain 
places than in others. Thus the drainage from the overlying 
clay is directed to certain points, where a greater amount of cal- 
careous matter is dissolved than elsewhere. Even narrow open 
channels are sometimes formed in the solid chalk. As the chalk 
is slowly dissolved over the whole country, but more in some 
parts than in others, the undissolved residue that is the over- 
lying mass of red clay with flints, likewise sinks slowly down, 
and tends to fill up the pipes or cavities. But the upper part 
of the red clay holds together, aided probably by the roots of 
plants, for a longer time than the lower parts, and thus forms 
a roof, which sooner or later falls in, as in the above mentioned 
five cases. The downward movement of the clay may be com- 
pared with that of a glacier, but is incomparably slower ; and this 
movement accounts for a singular fact, namely, that the much 
elongated flints which are embedded in the chalk in a nearly 
horizontal position, are commonly found standing nearly or quite 
upright in the red clay. This fact is so common that the work- 
men assured me that this was their natural position. I roughly 
measured one which stood vertically, and it was of the same 
length and of the same relative thickness as one of my arms. 
These elongated flints must get placed in their upright position, 



CHAP. III. BROUGHT UP BY WORMS. 141 

been left on the surface and forms a bed oi 
stiff red clay, full of flints, and generally 
from 6 to 14 feet in thickness. Over the red 
clay, wherever the land has long remained as 
pasture, there is a layer a few inches in 
thickness, of dark-coloured vegetable mould. 

A quantity of broken chalk was spread, 
on December 20, 1842, over a part of a field 
near my house, which had existed as pasture 
certainly for 30, probably for twice or thrice 
as many years. The chalk was laid on the 
land for the sake of observing at some future 
period to what depth it would become buried. 
At the end of November, 1871, that is after an 
interval of 29 years, a trench was dug across 
this part of the field; and a line of white nodules 
could be traced on both sides of the trench, at 
a depth of 7 inches from the surface. The 
mould, therefore, (excluding the turf) had 

on the same principle that a trunk of a tree left on a glacier 
assumes a position parallel to the line of motion. The flints 
iu the clay which form almost half its bulk, are very often 
broken, though not rolled or abraded ; and this may be ac- 
counted for by their mutual pressure, whilst the whole mass is 
subsiding. I may add that the chalk here appears to have been 
originally covered in parts by a thin bed of fine sand with some 
perfectly rounded flint pebbles, probably of Tertiary age ; for such 
sand often partly fills up the deeper pits or cavities iu the chalk. 



H2 AMOUNT OF EARTH CHAP. III. 

here been thrown tip at an average rate of 
*22 inch per year. Beneath the line of 
chalk nodules there was in parts hardly any 
fine earth free of flints, while in other parts 
there was a layer, 2 inches in thickness. In 
this latter case the mould was altogether 9i 
inches thick ; and in one such spot a nodule 
of chalk and a smooth flint pebble, both of 
which must have been left at some former 
time on the surface, were found at this 
depth. At from 11 to 12 inches beneath 
the surface, the undisturbed reddish clay, full 
of flints, extended. The appearance of the 
above nodules of chalk surprised me much 
at first, as they closely resembled water- 
worn pebbles, whereas the freshly-broken 
fragments had been angular. But on ex- 
amining the nodules with a lens, they no 
longer appeared water-worn, for their surfaces 
were pitted through unequal corrosion, and 
minute, sharp points, formed of broken fossil 
shells, projected from them. It was evident 
that the corners of the original fragments of 
chalk had been wholly dissolved , from pre- 
senting a large surface to the carbonic acid 
dissolved in the rain-water and to that gener- 



CHAP. III. BROUGHT UP BY WORMS. 143 

ated iii soil containing vegetable matter, as 
well as to the humus-acids.* The projecting 
corners would also, relatively to the other 
parts, have been embraced by a larger num- 
ber of living rootlets; and these have the 
power of even attacking marble, as Sachs has 
shown. Thus, in the course of 29 years, 
buried angular fragments of chalk had been 
converted into well-rounded nodules. 

Another part of this same field was mossy, 
and as it was thought that sifted coal- cinders 
would improve the pasture, a thick layer was- 
spread over this part either in 1842 or 1843 r 
and another layer some years afterwards. 
In 1871 a trench was here dug, and many 
cinders lay in a line at a depth of 7 
inches beneath the surface, with another line 
at a depth of 5J inches parallel to the one 
beneath. In another part of this field,, 
which had formerly existed as a separate 
one, and which it was believed had been 
pasture-land for more than a century, trenches 
were dug to see how thick the vegetable 
mould was. By chance the first trench was 
made at a spot where at some former period,. 

* S. W. Johnson, How Crops Feed,' 1870, p. 139. 



144 AMOUNT OF EARTH CHAP. III. 

certainly more than forty years before, a 
large hole had been filled Tip with coarse red 
clay, flints, fragments of chalk, and gravel ; 
and here the fine vegetable mould was only 
from 4-J- to 4| inches in thickness. In 
another and undisturbed place, the mould 
varied much in thickness, namely, from 6J 
to 8 inches; beneath which a few small 
fragments of brick were found in one 
place. From these several cases, it would 
appear that during the last 29 years mould 
has been heaped on the surface at an 
average annual rate of from '2 to *22 of an 
inch. But in this district when a ploughed 
field is first laid down in grass, the mould 
accumulates at a much slower rate. The 
rate, also, must become very much slower 
after a bed of mould, several inches in thick- 
ness, has been formed ; for the worms then 
live chiefly near the surface, and burrow 
down to a greater depth so as to bring up 
fresh earth from below, only during the 
winter when the weather is very cold (at 
which time worms were found in this field at 
a depth of 26 inches) and during summer, 
when the weather is very dry. 



CHAP. IIL BROUGHT UP BY WORMS. 145 

A field, which adjoins the one just de- 
scribed, slopes in one part rather -steeply 
(viz., at from 10 to 15) ; this part was last 
ploughed in 1841, was then harrowed and 
left to become pasture-land. For several 
years it was clothed with an extremely scant 
vegetation, and was so thickly covered with 
small and large flints (some of them half as 
large as a child's head) that the field was 
always called by my sons " the stony field." 
When they ran down the slope the stones 
clattered together. I remember doubting 
whether I should live to see these larger flints 
covered with vegetable mould and turf. But 
the smaller stones disappeared before many 
years had elapsed, as did every one of the 
larger ones after a time ; so that after thirty 
years (1871) a horse could gallop over the 
compact turf from one end of the field to the 
other, and not strike a single stone with his 
shoes. To anyone who remembered the 
appearance of the field in 1842, the transfor- 
mation was wonderful. This was certainly 
the work of the worms, for though castings 
were not frequent for several years, yet some 
were thrown up month after month, and 



146 AMOUNT OF EARTH CHAP. III. 

these gradually increased in numbers as the 
pasture improved. In the year 1871 a 
trench was dug on the above slope, and the 
blades of grass were cut off close to the roots, 
so that the thickness of the turf and of the 
vegetable mould could be measured accur- 
ately. The turf was rather less than half an 
inch, and the mould, which did not contain 
any stones, 2J inches in thickness. Beneath 
this lay coarse clayey earth full of flints, like 
that in any of the neighbouring ploughed 
fields. This coarse earth easily fell apart 
from the overlying mould when a spit was 
lifted up. The average rate of accumulation 
of the mould during the whole thirty years 
was only "083 inch per year (i.e., nearly one 
inch in twelve years) ; but the rate must 
have been much slower at first, and after- 
wards considerably quicker. 

The transformation in the appearance of 
this field, which had been effected beneath 
my eyes, was afterwards rendered the more 
striking, when I examined in Knole Park 
a dense) forest of lofty beech-trees, beneath 
which nothing grew. Here the ground was 
thickly strewed with large naked stones, and 



CHAP. III. BROUGHT UP BY WORMS. 147 

worm-castings were almost wholly absent. 
Obscure lines and irregularities on the sur- 
face indicated that the land had been cul- 
tivated some centuries ago. It is probable 
that a thick wood of young beech-trees 
sprung up so quickly, that time enough was 
not allowed for worms to cover up the stones 
with their castings, before the site became 
unfitted for their existence. Anyhow the con- 
trast between the state of the now miscalled 
" stony field," well stocked with worms, and 
the present state of the ground beneath the 
old beech-trees in Knole Park, where worms 
appeared to be absent, was striking. 

A narrow path running across part of my 
lawn was paved in 1843 with small flag- 
stones, set edgeways ; but worms threw up 
many castings and weeds grew thickly be- 
tween them. During several years the path 
was weeded and swept; but ultimately the 
weeds and worms prevailed, and the 
gardener ceased to sweep, merely mowing off 
the weeds, as often as the lawn was mowed. 
The path soon became almost covered up, 
and after several years no trace of it was 
left. On removing, in 1877, the thin over- 



148 AMOUNT OF EAETH CHAP. III. 

lying layer of turf, the small flag-stones, all 
in their proper places, were found covered 
by an inch of fine mould. 

Two recently published accounts of sub- 
stances strewed on the surface of pasture-land, 
having become buried through the action of 
worms, may be here noticed. The Rev. 
H. C. Key had a ditch cut in a field, over 
which coal-ashes had been spread, as it was 
believed, eighteen years before; and on the 
clean-cut perpendicular sides of the ditch, at a 
depth of at least seven inches, there could be 
seen, for a length of 60 yards, " a distinct, very 
" even, narrow line of coal-ashes, mixed with 
"small coal, perfectly parallel with the top- 
" sward."* This parallelism and the length of 
the section give interest to the case. Secondly, 
Mr. Dancer statesf that crushed bones had been 
thickly strewed over a field ; and " some years 
" afterwards " these were found "several inches 
" below the surface, at a uniform depth." 

The Rev. Mr. Zincke informs me that he 
has lately had an orchard dug to the unusual 
depth of 4 feet. The upper 18 inches consisted 

* ' Nature,' November 1877, p. 28. 

t * Proc. Phil. Soc.' of Manchester, 1877, p. 247. 






CHAP. III. BROUGHT UP BY WORMS. 149 

of dark-coloured vegetable mould, and the 
next 18 inches of sandy loam, containing in 
the lower part many rolled pieces of sand- 
stone, with some bits of brick and tile, probably 
of Roman origin, as remains of this period 
have been found close by. The sandy loam 
rested on an indurated ferruginous pan of 
yellow clay, on the surface of which two 
perfect celts were found. If, as seems pro- 
bable, the celts were originally left on the 
surface of the land, they have since been 
covered up with earth 3 feet in thickness, all 
of which has probably passed through the 
bodies of worms, excepting the stones which 
may have been scattered on the surface at 
different times, together with manure or by 
other means. It is difficult otherwise to 
understand the source of the 18 inches of 
sandy loam, which differed from the overlying 
dark vegetable mould, after both had been 
burnt, only in being of a brighter red colour, 
and in not being quite so fine-grained. But 
on this view we must suppose that the carbon 
in vegetable mould, when it lies at some little 
depth beneath the surface and does not con- 
tinually receive decaying vegetable matter 

M 2 



150 AMOUNT OF EAKTH CHAP. III. 

from above, loses its dark colour in the course 
of centuries ; but whether this is probable I 
do not know. 

Worms appear to act in the same manner 
in New Zealand as in Europe ; for Professor J. 
von Haast has described * a section near the 
coast, consisting of mica-schist, " covered by 
"5 or 6 feet of loess, above which about 12 
"inches of vegetable soil had accumulated." 
Between the loess and the mould there was 
a layer from 3 to 6 inches in thickness, 
consisting of " cores, implements, flakes, and 
" chips, all manufactured from hard basaltic 
"rock." It is therefore probable that the 
aborigines, at some former period, had left 
these objects on the surface, and that they 
had afterwards been slowly covered up by 
the castings of worms. 

Farmers in England are well aware that 
objects of all kinds, left on the surface of 
pasture-land, after a time disappear, or, as 
they say, work themselves downwards. How 
powdered lime, cinders, and heavy stones, 
can work down, and at the same rate, 
through the matted roots of a grass-covered 

* Trans, of the New Zealand Institute,' vol. xii., 1880, p. 152. 



CHAP. III. BROUGHT UP BY WORMS. 151 

surface, is a question which has probably 
never occurred to them.* 

The Sinking of great Stones through the 
Action of Worms. When a stone of large 
size and of irregular shape is left on the 
surface of the ground, it rests, of course, 
on the more protuberant parts ; but worms 
soon fill up with their castings all the hollow 
spaces on the lower side ; for, as Hensen re- 
marks, they like the shelter of stones. As 
soon as the hollows are filled up, the worms 
eject the earth which they have swallowed 
beyond the circumference of the stones ; 
and thus the surface of the ground is raised 
all round the stone. As the burrows ex- 
cavated directly beneath the stone after a 
time collapse, the stone sinks a little, t Hence 

* Mr. Lindsay Carnagie, in a letter (June 1838) to Sir C. Lyell, 
remarks that Scotch farmers are afraid of putting lime on 
ploughed land until just before it is laid down for pasture, from 
a belief that it has some tendency to sink. He adds : " Some 
years since, in autumn, I laid lime on an oat-stubble and ploughed 
it down ; thus bringing it into immediate contact with the dead 
vegetable matter, and securing its thorough mixture through the 
means of all the subsequent operations of fallow. In consequence 
of the above prejudice, I was considered to have committed a 
great fault ; but the result was eminently successful, and the 
practice was partially followed. By means of Mr. Darwin's 
observations, I think the prejudice will be removed." 

f This conclusion, which, as we shall immediately see, is fully 



152 GKEAT STONES CHAP. HI. 

it is, that boulders which at some ancient 
period have rolled down from a rocky moun- 
tain or cliff on to a meadow at its hase, are 
always somewhat imbedded in the soil ; and, 
when removed, leave an exact impression of 
their lower surfaces in the underlying fine 
mould. If, however, a boulder is of such 
huge dimensions, that the earth beneath is 
kept dry, such earth will not be inhabited 
by worms, and the boulder will not sink 
into the ground 

A lime-kiln formerly stood in a grass-field 
near Leith Hill Place in Surrey, and was 
pulled down 35 years before my visit; 
all the loose rubbish had been carted away, 
excepting three large stones of quartzose 
sandstone, which it was thought might here- 
after be of some use. An old workman re- 
membered that they had been left on a bare 
surface of broken bricks and mortar, close to 
the foundations of the kiln ; but the whole 
surrounding surface is now covered with turf 
and mould. The two largest of these stones 



justified, is of some little importance, as the so-called bench-stones> 
which surveyors fix in the ground as a record of their levels, 
may in time become false standards. My son Horace intends at 
some future period to ascertain how far this has occurred. 



CHAP. III. UNDERMINED BY WORMS. 153 

had never since been moved ; nor could this 
easily have been done, as, when I had them 
removed, it was the work of two men with 
levers. One of these stones, and not the 
largest, was 64 inches long, 17 inches broad, 
and from 9 to 10 inches in thickness. Its 
lower surface was somewhat protuberant in 
the middle ; and this part still rested on 
broken bricks and mortar, showing the truth 
of the old workman's account. Beneath the 
brick rubbish the natural sandy soil, full of 
fragments of sandstone was found ; and this 
could have yielded very little, if at all, to 
the weight of the stone, as might have been 
expected if the sub-soil had been clay. The 
surface of the field, for a distance of about 
9 inches round the stone, gradually sloped up 
to it, and close to the stone stood in most 
places about 4 inches above the surrounding 
ground. The base of the stone was buried 
from 1 to 2 inches beneath the general level, 
and the upper surface projected about 8 
inches above this level, or about 4 inches 
above the sloping border of turf. After the 
removal of the stone it became evident that 
one of its pointed ends must at first have 
stood clear above the ground by some inches, 



154 GREAT STONES CHAP. III. 

but its upper surface was now on a level 
with the surrounding turf. When the stone 
was removed, an exact cast of its lower 
side, forming a shallow crateriform hollow, 
was left, the inner surface of which consisted 
of fine black mould, excepting where the 
more protuberant parts rested on the brick- 
rubbish. A transverse section of this stone, 
together with its bed, drawn from measure- 




Fig. 6. 

Transverse section across a large stone, which had lain on a 
grass-field for 35 years. A A, general level of the field. The 
underlying brick rubbish has not been represented. Scale 
i inch to one foot. 

ments made after it had been displaced, is 
here given on a scale of J inch to a foot 
(Fig. 6). The turf-covered border which 
sloped up to the stone, consisted of fine 
vegetable mould, in one part 7 inches in 
thickness. This evidently consisted of worm- 
castings, several of which had been recently 
ejected. The whole stone had sunk in the 



CHAP. in. UNDERMINED BY WORMS. 155 

thirty-five years, as far as I could judge, 
about H inch ; and this must have been due 
to the brick-rubbish beneath the more pro- 
tuberant parts having been undermined by 
worms. At this rate the upper surface of the 
stone, if it had been left undisturbed, would 
have sunk to the general level of the field 
in 247 years; but before this could have 
occurred, some earth would have been washed 
down by heavy rain from the castings on the 
raised border of turf over the upper surface 
of the stone. 

The second stone was larger than the one 
just described, viz., 67 inches in length, 39 in 
breadth, and 15 in thickness. The lower 
surface was nearly flat, so that the worms 
must soon have been compelled to eject their 
castings beyond its circumference. The stone 
as a whole had sunk about 2 inches into the 
ground. At this rate it won Id have required 
262 years for its upper surface to have sunk 
to the general level of the field. The up- 
wardly sloping, turf-covered border round 
the stone was broader than in the last case, 
viz., from 14 to 16 inches; and why this 
should be so, I could see no reason. In most 
parts this border was not so high as in the 



156 GREAT STONES CHAP. III. 

last case, viz., from 2 to 2J inches, but in one 
place it was as much as 5J. Its average 
height close to the stone was probably about 
3 inches, and it thinned out to nothing. If 
so, a layer of fine earth, 15 inches in breadth 
and 1^ inch in average thickness, of sufficient 
length to surround the whole of the much 
elongated slab, must have been brought up 
by the worms in chief part from beneath the 
stone in the course of 35 years. This 
amount would be amply sufficient to account 
for its having sunk about 2 inches into the 
ground ; more especially if we bear in mind 
that a good deal of the finest earth would 
have been washed by heavy rain from the 
castings ejected on the sloping border down 
to the level of the field. Some fresh castings 
were seen close to the stone. Nevertheless, 
on digging a large hole to a depth of 18 
inches where the stone had lain, only two 
worms and a few burrows were seen, although 
the soil was damp and seemed favourable for 
worms. There were some large colonies of 
ants beneath the stone, and possibly since 
their establishment the worms had decreased 
in number. 

The third stone was only about half as 



CHAP. III. UNDERMINED BY WORMS. 157 

large as the others ; and two strong boys 
could together have rolled it over. I have 
no doubt that it had been rolled over at a 
moderately recent time, for it now lay at 
some distance from the two other stones at 
the bottom of a little adjoining slope. It 
rested also on fine earth, instead of partly on 
brick-rubbish. In agreement with this con- 
clusion, the raised surrounding border of 
turf was only 1 inch high in some parts, and 
2 inches in other parts. There were no 
colonies of ants beneath this stone, and on 
digging a hole where it had lain, several 
burrows and worms were found. 

At Stonehenge, some of the outer Druidical 
stones are now prostrate, having fallen at a 
remote but unknown period ; and these have 
become buried to a moderate depth in the 
ground. They are surrounded by sloping 
borders of turf, on which recent castings were 
seen. Close to one of these fallen stones, 
which was 17 ft. long, 6 ft. broad, and 28 \ 
inches thick, a hole was dug ; and here the 
vegetable mould was at least 9^ inches in 
thickness. At this depth a flint was found, 
and a little higher up on one side of the hole 
a fragment of glass. The base of the stone 



158 GREAT STONES CHAP. III. 

lay about 9 inches beneath the level of the 
surrounding ground, and its upper surface 
19 inches above the ground. 

A hole was also dug close to a second huge 
stone, which in falling had broken into two 
pieces; and this must have happened long 
ago, judging from the weathered aspect of 
the fractured ends. The base was buried to 
a depth of 10 inches, as was ascertained by 
driving an iron skewer horizontally into the 
ground beneath it. The vegetable mould 
forming the turf-covered sloping border round 
the stone, on which many castings had re- 
cently been ejected, was 10 inches in thick- 
ness ; and most of this mould must have been 
brought up by worms from beneath its base. 
At a distance of 8 yards from the stone, the 
mould was only 5^ inches in thickness (with 
a piece of tobacco pipe at a depth of 4 inches), 
and this rested on broken flint and chalk 
which could not have easily yielded to the 
pressure or weight of the stone. 

A straight rod was fixed horizontally (by 
the aid of a spirit-level) across a third fallen 
stone, which was 7 feet 9 inches long ; and the 
contour of the projecting parts and of the ad- 
Coining ground, which was not quite level, 



CHAP. III. UNDERMINED BY WORMS. 159 

was thus ascertained, as shown in the ac- 
companying diagram (Fig. 7) on a scale of 
^ inch to a foot. The turf-covered border 
sloped up to the stone on one side to a 
height of 4 inches, and on the opposite side 
to only 2 inches above the general level. 
A hole was dug on the eastern side, and the 
base of the stone was here found to lie at a 



Grass 




Fig. 7. 

Section through one of the fallen Druidical stones at Stonehenge, 
showing how much it had sunk into the ground. Scale inch 
to 1 foot. 

depth of 4 inches beneath the general level 
of the ground, and of 8 inches beneath the 
top of the sloping turf-covered border. 

Sufficient evidence has now been given 
showing that small objects left on the surface 
of the land where worms abound soon get 
buried, and that large stones sink slowly 
downwards through the same means. Every 



160 GREAT STONES CHAP. III. 

step of the process could be followed, from the 
accidental deposition of a single casting on a 
small object lying loose on the surface, to its 
being entangled amidst the matted roots of 
the turf, and lastly to its being imbedded in 
the mould at various depths beneath the 
surface. When the same field was re-ex- 
amined after the interval of a few years, such 
objects were found at a greater depth than 
before. The straightness and regularity of 
the lines formed by the imbedded objects, 
and their parallelism with the surface of the 
land, are the most striking features of the 
case ; for this parallelism shows how equably 
the worms must have worked; the result 
being, however, partly the effect of the wash- 
ing down of the fresh castings by rain. The 
specific gravity of the objects does not affect 
their rate of sinking, as could be seen by 
porous cinders, burnt marl, chalk and quartz 
pebbles, having all sunk to the same depth 
within the same time. Considering the 
nature of the substratum, which at Leith Hill 
Place was sandy soil including many bits of 
rock, and at Stonehenge, chalk-rubble with 
broken flints; considering, also, the presence 
of the turf-covered sloping border of mould 



CHAP. III. UNDERMINED BY WORMS. 161 

round the great fragments of stone at both 
these places, their sinking does not appear to 
have been sensibly aided by their weight, 
though this was considerable.* 

On the number of worms which live within 
a given space. We will now show, firstly, 
what a vast number of worms live unseen by 
us beneath our feet, and, secondly, the actual 
weight of the earth which they bring up to 
the surface within a given space and within 
a given time. Hensen, who has published so 
full and interesting an account of the habits 
of worms,f calculates, from the number which 
he found in a measured space, that there must 
exist 133,000 living worms in a hectare of 
land, or 53,767 in an acre. This latter 
number of worms would weigh 356 pounds, 
taking Hensen's standard of the weight of a 
single worm, namely, three grams. It should, 
however, be noted that this calculation is 

* Mr. R. Mallet remarks (' Quarterly Journal of Geolog. Soc.' 
vol. xxxiii., 1877, p. 745) that " the extent to which the ground 
beneath the foundations of ponderous architectural structures, 
such as cathedral towers, has been known to become compressed, 
is as remarkable as it is instructive and curious. The amount 
of depression in some cases may be measured by feet." He 
instances the Tower of Pisa, but adds that it was founded on 



f ' Zeitschrift fur wissensch. Zoolog.' Bd.xxviii., 1877, p. 360. 



162 WEIGHT OF EAKTH CHAP. III. 

founded on the numbers found in a garden, 
and Hensen believes that worms are here 
twice as numerous as in corn-fields. The 
above result, astonishing though it be, seems 
to me credible, judging from the number of 
worms which I have sometimes seen, and 
from the number daily destroyed by birds 
without the species being exterminated. 
Some barrels of bad ale were left on Mr. 
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 considerable body of 
water in which worms were immersed, in- 
variably killed them quickly. On the morn- 
ing after the barrels had been upset, " the 
" heaps of worms which lay dead on the 
" ground were so amazing, that if Mr. Miller 
" had not seen them, he could not have 
"thought it possible for such numbers to 
" have existed in the space." As further evi- 
dence 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 Manchester/' 
1877, p. 248. 



CHAP. III. BROUGHT UP BY WORMS. 163: 

found in a garden sixty-four open burrows in 
a space of 14i square feet, that is, nine in 
2 square feet. But the burrows are some- 
times much more numerous, for when digging 
in a grass-field near Maer Hall, I found a 
cake of dry earth, as large as my two open 
hands, which was penetrated by seven bur- 
rows, as large as goose-quills. 

Weight of the earth ejected from a single 
burrow, and from all the burrows within a 
given space. With respect to the weight of 
the earth daily ejected by worms, Hensen 
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 less than 8 grains per 
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 are 
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 



164 WEIGHT OF EARTH CHAP. III. 

castings were dried (excepting in one specified 
instance) by exposure during many days to 
the sun or before a hot fire. 
WEIGHT OF THE CASTINGS ACCUMULATED AT THE MOUTH 

OF A SINGLE BuBBOW. 

Ounces 

(1.) Down, Kent (sub-soil red clay, full of flints, over- 
lying the chalk). The largest casting which I 
could find on the flanks of a steep valley, the 3 '98 
sub-soil being here shallow. In this one case, the 
casting was not well dried 

(2.) Down. Largest casting which I could find (con-] 
sisting chiefly of calcareous matter), on extremely I -3.07 
poor pasture land at the bottom of the valley! 
mentioned under (1.) .. .. .. ..' 

(3.) Down. A large casting, but not of unusual size,) 

from a nearly level field, poor pasture, laid down in / 1 * 22 
grass about 35 years before . . . . . . . . ) 

(4.) Down. Average weight of 11 not large castings j 

ejected on a sloping surface on my lawn, after they! Q - 
had suffered some loss of weight from being exposed j 
during a considerable length of time to rain . . J 

(5.) Near Nice in France. Average weight of 12' 
castings of ordinary dimensions, collected by Dr. 
King on land which had not been mown for a long 
time and where worms abounded, viz., a lawn pro- 
tected by shrubberies, near the sea ; soil sandy and 1*37 
calcareous ; these castings had been exposed for some 
time to rain, before being collected, and must have 
lost some weight by disintegration, but they still re- 
tained their form 

(6.) The heaviest of the above twelve castings .. 1*76 

'7.) Lower Bengal. Average weight of 22 castings, 
collected by Mr. J. Scott, and stated by him to have 1 24 
been thrown up in the course of one or two nights 

(8.) The heaviest of the above 22 castings .. .. 2'09 

(9.) Nilgiri Mountains, S. India ; average weight of-j 

the 5 largest castings collected by Dr. King. They! 3>15 
had been exposed to the rain of the last monsoon, j 
and must have lost some weight .. .. .. J 

(10.) The heaviest of the above 5 castings .. .. 4-34 

In thi& table we see that castings which had 



CHAP. III. BEOUGHT UP BY WORMS. 165 

been ejected at the mouth of the same burrow, 
and which in most cases appeared fresh and 
always retained their vermiform configuration, 
generally exceeded an ounce in weight after 
being dried, and sometimes nearly equalled a 
quarter of a pound. On the Nilgiri moun- 
tains one casting even exceeded this latter 
weight. The largest castings in England 
were found on extremely poor pasture-land; 
and these, as far as I have seen, are generally 
larger than those on land producing a rich 
vegetation. It would appear that worms 
have to swallow a greater amount of earth 
on poor than on rich land, in order to obtain 
sufficient nutriment. 

With respect to the tower-like castings 
near Nice (Nos. 5 and 6 in the above table), 
Dr. King often found five or six of them on 
a square foot of surface ; and these, judging 
from their average weight, would have 
weighed together 7^ ounces; so that the 
weight of those on a square yard would 
have been 41b. 3oz, Dr. King collected, 
near the close of the year 1872, all the 
castings which still retained their vermiform 
shape, whether broken down or not, from a 

N 2 



166 WEIGHT OF EARTH CHAP. IIL 

square foot, in a place abounding with worms, 
on the summit of a bank, where no castings 
could have rolled down from above. These 
castings must have been ejected, as he judged 
from their appearance in reference to the 
rainy and dry periods near Nice, within the 
previous five or six months ; they weighed 
9|oz., or 5 Ib. 5^oz. per square yard. After 
an interval of four months, Dr. King collected 
all the castings subsequently ejected on the 
same square foot of surface, and they weighed 
2J oz., or 1 Ib. 6^ oz. per square yard. 
Therefore within about ten months, or we 
will say for safety's sake within a year, 12 oz. 
of castings were thrown up on this one 
square foot, or 6*75 pounds on the square 
yard ; and this would give 14*58 tons per 
acre. 

In a field at the bottom of a valley in the 
chalk (see No. 2 in the foregoing table), a 
square yard was measured at a spot where 
very large castings abounded ; they appeared, 
however, almost equally numerous in a few 
other places. These castings, which retained 
perfectly their vermiform shape, were col- 
lected ; and they weighed when partially 
dried, 1 Ib. 13J oz. This field had been 



CH*P. III. BROUGHT UP BY WORMS. 167 

rolled with a heavy agricultural roller fifty-two 
days before, and this would certainly have 
flattened every single casting on the land. 
The weather had been very dry for two or 
three weeks before the day of collection, so 
that not one casting appeared fresh or had 
been recently ejected. We may therefore 
assume that those which were weighed had 
been ejected within, we will say, forty days 
from the time when the field was rolled, 
that is, twelve days short of the whole inter- 
vening period. I had examined the same 
part of the field shortly before it was rolled, 
and it then abounded with fresh castings. 
Worms do not work in dry weather during 
the summer, or in winter during severe frosts. 
If we assume that they work for only half 
the year though this is too low an estimate 
then the worms in this field would eject 
during the year, 8'38 7 pounds per square yard ; 
or 18' 12 tons per acre, assuming the whole 
surface to be equally productive in castings. 

In the foregoing cases some of the 
necessary data had to be estimated, but in 
the two following cases the results are much 
more trustworthy. A lady, on whose ac- 
curacy I can implicitly rely, offered to collect 



168 WEIGHT OF EAETH CHAP. III. 

during a year all the castings thrown up on 
two separate square yards, near Leith Hill 
Place, in Surrey. The amount collected was, 
however, somewhat less than that originally 
ejected by the worms ; for, as I have repeatedly 
observed, a good deal of the finest earth is 
washed away, whenever castings are thrown up 
during or shortly before heavy rain. Small 
portions also adhered to the surrounding 
blades of grass, and it required too much 
time to detach every one of them. On 
sandy soil, as in the present instance, castings 
are liable to crumble after dry weather, and 
particles were thus often lost. The lady also 
occasionally left home for a week or two, and 
at such times the castings must have suffered 
still greater loss from exposure to the weather. 
These losses were, however, compensated to 
some extent by the collections having been 
made on one of the squares for four days, and 
on the other square for two days more than 
the year. 

A space was selected (October 9th, 1870) for 
one of the squares on a broad, grass-covered 
terrace, which had been mowed and swept 
during many years. It faced the south, but 



CHAP. III. BROUGHT UP BY WORMS. 169 

was shaded during part of the day by trees. 
It had been formed at least a century ago by 
a great accumulation of small and large frag- 
ments of sandstone, together with some sandy 
earth, rammed down level. It is probable that 
it was at first protected by being covered with 
turf. This terrace, judging from the number 
of castings on it, was rather unfavourable for 
the existence of worms, in comparison with 
the neighbouring fields and an upper terrace. 
It was indeed surprising that as many worms 
could live here as were seen; for on digging 
a hole in this terrace, the black vegetable 
mould together with the turf was only four 
inches in thickness, beneath which lay the 
level surface of light-coloured sandy soil, with 
many fragments of sandstone. Before any 
castings were collected all the previously 
existing ones were carefully removed. The 
last day's collection was on October 14th, 
1871. The castings were then well dried 
before a fire ; and they weighed exactly 3^ Ibs. 
This would give for an acre of similar land 
7*56 tons of dry earth annually ejected by 
worms. 

The second square was marked on un- 



170 WEIGHT OF EARTH CHAP. IIL 

enclosed common land, at a height of about 
700 ft. above the sea, at some little distance 
from Leith Hill Tower. The surface was 
clothed with short, fine turf, and had never 
-been disturbed by the hand of man. The 
spot selected appeared neither particularly 
favourable nor the reverse for worms ; but I 
have often noticed that castings are especially 
abundant on common land, and this may, 
perhaps, be attributed to the poorness of 
the soil. The vegetable mould was here 
between three and four inches in thickness. 
As this spot was at some distance from the 
house where the lady lived, the castings were 
not collected at such short intervals of time 
as those on the terrace ; consequently the 
loss of fine earth during rainy weather must 
have been greater in this than in the last 
case. The castings moreover were more 
sandy, and in collecting them during dry 
weather they sometimes crumbled into dust, 
and much was thus lost. Therefore it is 
certain that the worms brought up to the 
surface considerably more earth than that 
which was collected. The last collection 
was made on October 27th, 1871 ; i.e., 367 



CHAP. III. BEOUGHT UP BY WORMS. 171 

days after the square had been marked out 
and the surface cleared of all pre-existing 
castings. The collected castings, after being 
well dried, weighed 7*453 pounds ; and this 
would give, for an acre of the same kind of 
land, 16'1 tons of annually ejected dry earth. 

SUMMARY OF THE FOUR FOREGOING CASES. 

(1.) Castings ejected near Nice within about a year, collected 
by Dr. King on a square foot of surface, calculated to yield per 
acre 14 '58 tons. 

(2.) Castings ejected during about 40 days on a square yard, 
in a field of poor pasture at the bottom of a large valley in the 
Chalk, calculated to yield annually per acre 18 '12 tons. 

(3.) Castings collected from a square yard on an old terrace at 
Leith Hill Place, during 369 days, calculated to yield annually 
per acre 7 "56 tons. 

(4.) Castings collected from a square yard on Leith Hill 
Common during 367 days, calculated to yield annually per acre 
16-1 tons. 

The thickness of the layer of mould, which 
castings ejected during a year would form if 
uniformly spread out. As we know, from 
the two last cases in the above summary, the 
weight of the dried castings ejected by worms 
during a year on a square yard of surface, I 
wished to learn how thick a layer of ordinary 
mould this amount would form if spread uni- 
formly over a square yard. The dry castings 



172 THICKNESS OF THE MOULD CHAP. III. 

were therefore broken into small particles, 
and whilst being placed in a measure were 
well shaken and pressed down. Those col- 
lected on the Terrace amounted to 124*77 
cubic inches ; and this amount, if spread out 
over a square yard, would make a layer 
0*9627 inch in thickness. Those collected on 
the Common amounted to 197*56 cubic inches, 
and would make a similar layer *1524 inch in 
thickness. 

These thicknesses must, however, be cor- 
rected, for the triturated castings, after being 
well shaken down and pressed, did not make 
nearly so compact a mass as vegetable mould, 
though each separate particle was very 
compact. Yet mould is far from being com- 
pact, as is shown by the number of air- 
bubbles which rise up when the surface is 
flooded with water. It is moreover pene- 
trated by many fine roots. To ascertain ap- 
proximately by how much ordinary vegetable 
mould would be increased in bulk by being 
broken up into small particles and then dried, 
a thin oblong block of somewhat argillaceous 
mould (with the turf pared off) was measured 
before being broken up, was well dried and 



CHAP. IIL ANNUALLY ACCUMULATED. 17S 

again measured. The drying caused it to 
shrink by ^ of its original bulk, judging from 
exterior measurements alone. It was then 
triturated and partly reduced to powder, in the 
same manner as the castings had been treated, 
and its bulk now exceeded (notwithstanding 
shrinkage from drying) by -j^g- that of the 
original block of damp mould. Therefore the 
above calculated thickness of the layer, formed 
by the castings from the Terrace, after being 
damped and spread over a square yard, would 
have to be reduced by T ^-; and this will 
reduce the layer to '09 of an inch, so that a 
layer '9 inch in thickness would be formed in 
the course of ten years. On the same prin- 
ciple the castings from the Common would 
make in the course of a single year a layer 
1429 inch, or in the course of 10 years 1*429 
inch, in thickness. We may say in round 
numbers that the thickness in the former case 
rould amount to nearly 1 inch, and in- the 
second case to nearly 1J inch in 10 years. 

In order to compare these results with 
those deduced from the rates at which small 
objects left on the surfaces of grass-fields 
become buried (as described in the early part 



174 THICKNESS OF THE MOULD CHAP. III. 

of this chapter), we will give the following 
summary : 

SUMMARY OF THE THICKNESS OF THE MOULD ACCUMULATED 
OVER OBJECTS LEFT STREWED ON THE SURFACE, IN THE 
COURSE OF TEN YEARS. 

The accumulation of mould during 14f years on the surface 
of a dry, sandy, grass-field near Maer Hall, amounted to 2'2 
inches in 10 years. 

The accumulation during 21i years on a swampy field near 
Maer Hall, amounted to nearly 1'9 inch in 10 years. 

The accumulation during 7 years on a very swampy field near 
Maer Hall amounted to 2 1 inches in 10 years. 

The accumulation during 29 years, on good, argillaceous 
pasture-land over the Chalk at Down, amounted to 2*2 inches in 
10 years. 

The accumulation during 30 years on the side of a valley over 
the Chalk at Down, the soil being argillaceous, very poor, and 
only just converted into pasture (so that it was for some years 
unfavourable for worms), amounted to P 83 inch in 10 years. 

In these cases (excepting the last) it may 
be seen that the amount of earth brought 
to the surface during 10 years is somewhat 
greater than that calculated from the castings 
which were actually weighed. This excess 
may be partly accounted for by the loss which 
the weighed castings had previously under- 
gone through being washed by rain, by the 
adhesion of particles to the blades of the sur- 
rounding grass, and by their crumbling when 
dry. Nor must we overlook other agencies 



CHAP. III. ANNUALLY ACCUMULATED. 175 

which in all ordinary cases add to the 
amount of mould, and which would not be 
included in the castings that were collected, 
namely, the fine earth brought up to the 
surface by burrowing larvse and insects, espe- 
cially by ants. The earth brought up by moles 
generally has a somewhat different appearance 
from vegetable mould ; but after a time would 
not be distinguishable from it. In dry coun- 
tries, moreover, the wind plays an important 
part in carrying dust from one place to another, 
and even in England it must add to the mould 
on fields near great roads. But in our country 
these latter several agencies appear to be of 
quite subordinate importance in comparison 
with the action of worms. 

We have no means of judging how great a 
weight of earth a single full-sized worm ejects 
during a year. Hensen estimates that 53,767 
worms exist in an acre of land; but this is 
founded on the number found in gardens, and 
he believes that only about half as many live 
in corn-fields. How many live in old pasture 
land is unknown ; but if we assume that half 
the above number, or 26,886 worms live on 
such land, then taking from the previous 



176 THICKNESS OF THE MOULD CHAP. III. 

summary 15 tons as the weight of the castings 
annually thrown up on an acre of land, each 
worm must annually eject 20 ounces. A full- 
sized casting at the mouth of a single burrow 
often exceeds, as we have seen, an ounce in 
weight ; and it is probable that worms eject 
more than 20 full-sized castings during a 
year. If they eject annually more than 20 
ounces, we may infer that the worms which 
live in an acre of pasture land must be less 
than 26,886 in number. 

"Worms live chiefly in the superficial mould, 
which is usually from 4 or 5 to 10 and even 
12 inches in thickness; and it is this mould 
which passes over and over again through 
their bodies and is brought to the surface. 
But worms occasionally burrow into the sub- 
soil to a much greater depth, and on such 
occasions they bring up earth from this 
greater depth ; and this process has gone on 
for countless ages. Therefore the superficial 
layer of mould would ultimately attain, 
though at a slower and slower rate, a thick- 
ness equal to the depth to which worms 
ever burrow, were there not other opposing 
agencies at work which carry away to a 



CHAP. III. ANNUALLY ACCUMULATED. 177 

lower level some of the finest earth which is 
continually being brought to the surface by- 
worms. How great a thickness vegetable 
mould ever attains, I have not had good 
opportunities for observing; but in the next 
chapter, when we consider the burial of 
ancient buildings, some facts will be given on 
this head. In the two last chapters we 
shall see that the soil is actually increased, 
though only to a small degree, through the 
agency of worms; but .their chief work is 
to sift the finer from the coarser particles, to 
mingle the whole with, vegetable debris, and 
to saturate it with their intestinal secretions. 

Finally, no one who considers the facts 
given in this chapter on the burying of 
small objects and on the sinking of great 
stones left on the surface on the vast 
number of worms which live within a 
moderate extent of ground on the weight of 
the castings ejected from the mouth of the 
same burrow on the weight of all the cast- 
ings ejected within a known time on a measured 
space will hereafter, as I believe, doubt that 
worms play an important part in nature. 



178 BURIAL OF THE REMAINS CHAP. IV. 



CHAPTER IV. 

THE PART WHICH WORMS HAVE PLAYED IN 
THE BURIAL OF ANCIENT BUILDINGS. 

The accumulation of rubbish on the sites of great cities inde- 
pendent of the action of worms The burial of a Roman villa 
at Abinger The floors and walls penetrated by worms 
Subsidence of a modern pavement The buried pavement at 
Beaulieu Abbey Roman villas at Chedworth and Brading 
The remains of the Roman town at Silchester The nature of 
the debris by which the remains are covered The penetration 
of the tesselated floors and walls by worms Subsidence of 
the floors Thickness of the mould The old Roman city of 
"Wroxeter Thickness of the mould Depth of the foundations 
of some of the Buildings Conclusion. 

ARCHAEOLOGISTS are probably not aware how 
much they owe to worms for the preservation 
of many ancient objects. Coins, gold orna- 
ments, stone implements, &c., if dropped on 
the surface of the ground, will infallibly be 
buried by the castings of worms in a few 
years, and will thus be safely preserved, until 
the land at some future time is turned up. 
For instance, many years ago a grass-field 



CHAP. IV. OF ANCIENT BUILDINGS. 179 

was ploughed on the northern side of the 
Severn, not far from Shrewsbury ; and a 
surprising number of iron arrow-heads were 
found at the bottom of the furrows, which, as 
Mr. Blakeway, a local antiquary, believed, 
were relics of the battle of Shrewsbury in the 
year 1403, and no doubt had been originally 
left strewed on the battle-field. In the 
present chapter I shall show that not only 
implements, &c., are thus preserved, but that 
the floors and the remains of many ancient 
buildings in England have been buried so 
effectually, in large part through the action 
of worms, that they have been discovered in 
recent times solely through various accidents. 
The enormous beds of rubbish, several yards 
in thickness, which underlie many cities, 
such as Eome, Paris, and London, the lower 
ones being of great antiquity, are not here 
referred to, as they have not been in any 
way acted on by worms. When we con- 
sider how much matter is daily brought into 
a great city for building, fuel, clothing and 
food, and that in old times when the roads 
were bad and the work of the scavenger 
was neglected, a comparatively small amount 

o 



180 BURIAL OF THE REMAINS CHAP. IV. 

was carried away, we may agree with 
Elie de Beaumont, who, in discussing this 
subject, says, " pour une voiture de materiaux 
" qui en sort, on y en fait entrer cent." * Nor 
should we overlook the effects of fires, the 
demolition of old buildings, and the removal 
of rubbish to the nearest vacant space. 

AUnger, Surrey. Late in the autumn of 
1876, the ground in an old farm-yard at this 
place was dug to a depth of 2 to 2^ feet, and 
the workmen found various ancient remains. 
This led Mr. T. H. Farrer of Abinger Hall to 
have an adjoining ploughed field searched. 
On a trench being dug, a layer of concrete, 
still partly covered with tesserae (small red 
tiles), and surrounded on two sides by broken- 
down walls, was soon discovered. Ift is 
believed f that this room formed part of the 
atrium or reception-room of a Roman villa. 
The walls of two. or three other small rooms 
were afterwards discovered. Many fragments 
of pottery, other objects, and coins of several 

* ' Lecons de Geologic pratique,' 1845, p. 142. 

t A short account of this discovery was published in ' The 
Times' of January 2, 1879; and a fuller account in 'The 
Builder,' January 5, 1878. 



CHAP. IV. OF ANCIENT BUILDINGS. 181 

Roman emperors, dating from 133 to 361, and 
perhaps to 375 A.D., were likewise found. 
Also a half-penny of George I., 1715. The 
presence of this latter coin seems an anomaly ; 
but no douht it was dropped on the ground 
during the last century, and since then there 
has been ample time for its burial under a 
considerable depth of the castings of worms. 
From the different dates of the Roman coins 
we may infer that the building was long 
inhabited. It was probably ruined and 
deserted 1400 or 1500 years ago. 

I was present during the commencement of 
the excavations (August 20, 1877) and Mr. 
Farrer had two deep trenches dug at opposite 
ends of the atrium, so that I might examine 
the nature of the soil near the remains. 
The field sloped from east to west at an angle 
of about 7 ; and one of the two trenches, 
shown in the accompanying section (Fig. 8) 
was at the upper or eastern end. The 
diagram is on a scale of ^j of an inch to an 
inch ; but the trench, which was between 4 
and 5 feet broad, and in parts above 5 feet 
deep, has necessarily been reduced out of all 
proportion. - The fine mould over the floor 

o 2 



:182 



BURIAL OF THE REMAINS CHAP. IV. 




Fig. 8. 



Section through the foundations of a buried Roman villa at 
Abinger. A A, vegetable mould ; B, dark earth full of stones, 
13 inches in thickness ; C, black mould ; D, broken mortar ; 
E, black mould; F F, undisturbed sub-soil; G, tessera ; H, 
concrete ; I, nature unknown ; \V, buried wall. 



CHAP. IV. OF ANCIENT BUILDINGS. 183 '> 

of the atrium varied in thickness from 11 
to 16 inches; and on the side of the trench in. 
the section was a little over 13 inches. After 
the mould had been removed, the floor 
appeared as a whole moderately level ; but it 
sloped in parts at an angle of 1, and in one- 
place near the outside at as much as 8 30', 
The wall surrounding the pavement was- 
built of rough stones, and was 23 inches in: 
thickness where the trench was dug. Its 
broken summit was here 13 inches, but in 
another part 15 inches, beneath the surface of 
the field, being covered by this thickness of 
mould. In one spot, however, it rose to- 
within 6 inches of the surface. On two- 
sides of the room, where the junction of the- 
concrete floor with the bounding walls could 
be carefully examined, there was no crack or 
separation. This trench afterwards proved* 
to have been dug within an adjoining room 
(11 ft. by 11 ft. 6 in. in size), the existence of 
which was not even suspected whilst I was 
present. 

On the side of the trench farthest from the 
buried wall (W), the mould varied from 9 to 
14 inches in thickness ; it rested on a mass (B) 



4 
184 BURIAL OP THE REMAINS CHAP. IV. 

23 inches thick of blackish earth, including 
many large stones. Beneath this was a thin 
bed of very black mould (C), then a layer of 
earth full of fragments of mortar (D), and 
then another thin bed (about 3 inches thick) 
(E) of very black mould, which rested on the 
undisturbed subsoil (F) of firm, yellowish, 
argillaceous sand. The 23-inch bed (B) was 
probably made ground, as this would have 
brought up the floor of the room to a level 
with that of the atrium. The two thin beds 
of black mould at the bottom of the trench 
evidently marked two former land-surfaces. 
Outside the walls of the northern room, many 
bones, ashes, oyster-shells, broken pottery and 
an entire pot were subsequently found at a 
depth of 1 6 inches beneath the surface. 

The second trench was dug on the western 
or lower side of the villa: the mould was 
here only 6J inches in thickness, and it 
rested on a mass of fine earth full of stones, 
broken tiles and fragments of mortar, 34 
inches in thickness, beneath which was the 
undisturbed sand. Most of this earth had 
probably been washed down from the upper 
part of the field, and the fragments of 



CHAP. IV. OP ANCIENT BUILDINGS. 185 

stones, tiles, &c., must have come from the 
immediately adjoining ruins. 

It appears at first sight a surprising fact 
that this field of light sandy soil should have 
been cultivated and ploughed during many 
years, and that not a vestige of these buildings 
should have been discovered. No one even 
suspected that the remains of a Roman 
villa lay hidden close beneath the surface. 
But the fact is less surprising when it is 
known that the field, as the bailiff believed, 
had never been ploughed to a greater depth 
than 4 inches. It is certain that when the 
land was first ploughed, the pavement and 
the surrounding broken walls must have been 
covered by at least 4 inches of soil, for other- 
wise the rotten concrete floor would have 
been scored by the ploughshare, the tessera 
torn up, and the tops of the old walls 
knocked down. 

When the concrete and tesseras were first 
cleared over a space of 14 by 9 ft., the floor 
which was coated with trodden-down earth 
exhibited no signs of having been penetrated 
by worms ; and although the overlying fine 
jnould closely resembled that which in many 



186 BURIAL OF THE REMAINS CHAP. IV, 

places has certainly been accumulated by 
worms, yet it seemed hardly possible that this 
mould could have been brought up by worms 
from beneath the apparently sound floor. It 
seemed also extremely improbable that the 
thick walls, surrounding the room and still 
united to the concrete, had been undermined 
by worms, and had thus been caused to sink, 
being afterwards covered up by their cast- 
ings. I therefore at first concluded that all 
the fine mould above the ruins had been 
washed down from the upper parts of the 
field ; but we shall soon see that this conclu- 
sion was certainly erroneous, though much 
fine earth is known to be washed down from 
the upper part of the field in its present 
ploughed state during heavy rains. 

Although the concrete floor did not at 
first appear to have been anywhere pene- 
trated by worms, yet by the next morning 
little cakes of the trodden-down earth had 
been lifted up by worms over the mouths of 
seven burrows, which passed through the 
softer parts of the naked concrete, or between 
the interstices of the tesserae. On the third 
morning twenty-five burrows were counted ; 



CHAP. IV. OF ANCIENT BUILDINGS. 187 

and by suddenly lifting up the little cakes 
of earth, four worms were seen in the act 
of quickly retreating. Two castings were 
thrown up during the third night on the 
floor, and these were of large size. The 
season was not favourable for the full activity 
of worms, and the weather had lately been 
hot and dry, so that most of the worms now 
lived at a considerable depth. In digging 
the two trenches many open burrows and 
some worms were encountered at between 
30 and 40 inches beneath the surface ; but at 
a greater depth they became rare. One 
worm, however, was cut through at 48 J, and 
another at 51 J inches beneath the surface. 
A fresh humus-lined burrow was also met 
with at a depth of 57 and another at G5J 
inches. At greater depths than this, neither 
burrows nor worms were seen. 

As I wished to learn how many worms 
lived beneath the floor of the atrium a 
space of about 14 by 9 feet Mr. Farrer 
was so kind as to make observations for 
me, during the next seven weeks, by which 
time the worms in the surrounding country 
were in full activity, and were working 



188 BURIAL OF THE REMAINS CHAP. IV. 

near the surface. It is very improbable that 
worms should have migrated from the adjoin- 
ing field into the small space of the atrium, 
:after the superficial mould in which they 
prefer to live, had been removed. We may 
iherefore conclude that the burrows and the 
castings which were seen here during the 
ensuing seven weeks were the work of the 
former inhabitants of the space. I will now 
give a few extracts from Mr. Farrer's notes. 

Aug. 26th, 1877; that is, five days after 
ihe floor had been cleared. On the previous 
night there had been some heavy rain, which 
washed the surface clean, and now the mouths 
of forty burrows were counted. Parts of the 
concrete were seen to be solid, and had never 
been penetrated by worms, and here the rain- 
water lodged. 

Sept. 5th. Tracks of worms, made during 
the previous night, could be seen on the sur- 
face of the floor, and five or six vermiform 
castings had been thrown up. These were 
defaced. 

Sept. 12th. During the last six days, the 
worms have not been active, though many 
castings have been ejected in the neighbour- 



HAP. IV. OF ANCIENT BUILDINGS. 189 

ing fields ; but on this day the earth was a 
little raised over the mouths of the burrows, 
or castings were ejected, at ten fresh points. 
These were defaced. It should be understood 
that when a fresh burrow is spoken of, this 
generally means only that an old burrow has 
been re-opened. Mr. Farrer was repeatedly 
struck with the pertinacity with which the 
worms re-opened their old burrows, even when 
no earth was ejected from them. I have 
often observed the same fact, and generally 
the mouths of the burrows are protected by 
an accumulation of pebbles, sticks or leaves. 
Mr. Farrer likewise observed that the worms 
living beneath the floor of the atrium often 
collected coarse grains of sand, and such little 
stones as they could find, round the mouths 
of their burrows. 

Sept. 13th ; soft wet weather. The mouths 
of the burrows were re-opened, or castings 
were ejected, at 31 points; these were all 
defaced. 

Sept. 14th; 34 fresh holes or castings; 
all defaced. 

Sept. 15th ; 44 fresh holes, only 5 castings ; 
all defaced. 



190 BUEIAL OF THE EEMAINS CHAP. IV. 

Sept. 18th ; 43 fresh holes, 8 castings ; all 
defaced. 

The number of castings on the surrounding 
fields was now very large 

Sept. 19th; 40 holes, 8 castings; all 
defaced. 

Sept. 22nd. ; 43 holes, only a few fresh 
castings ; all defaced. 

Sept. 23rd ; 44 holes, 8 castings. 

Sept. 25th ; 50 holes, no record of the 
number of castings. 

Oct. 13th ; 61 holes, no record of the 
number of castings. 

After an interval of three years, Mr. Farrer, 
at my request, again looked at the concrete 
floor, and found the worms still at work. 

Knowing what great muscular power worms 
possess, and seeing how soft the concrete was- 
in many parts, I was not surprised at its 
having been penetrated by their burrows; 
but it is a more surprising fact that the 
mortar between the rough stones of the thick 
walls, surrounding the rooms, was found by 
Mr. Farrer to have been penetrated by worms. 
On August 26th, that is, five days after the 
ruins had been exposed, he observed four 



CHAP. IV. OF ANCIENT BUILDINGS. 191 

open burrows on the broken summit of the 
eastern wall (W in Fig. 8) ; and, on Septem- 
ber 15th, other burrows similarly situated 
were seen. -It should also be noted that in 
the perpendicular side of the trench (which 
was much deeper than is represented in 
Fig. 8) three recent burrows were seen, which 
ran obliquely far down beneath the base of 
the old wall. 

We thus see that many worms lived beneath 
the floor and the walls of the atrium at the 
time when the excavations were made ; and 
that they afterwards almost daily brought up 
earth to the surface from a considerable 
depth. There is not the slightest reason to 
doubt that worms have acted in this manner 
ever since the period when the concrete was 
sufficiently decayed to allow them to penetrate 
it; and even before that period they would 
have lived beneath the floor, as soon as it 
became pervious to rain, so that the soil 
beneath was kept damp. The floor and the 
walls must therefore have been continually 
undermined ; and fine earth must have been 
heaped on them during many centuries, 
perhaps for a thousand years. If the burrows 



192 BUKIAL OF THE EEMAINS CHAP. IV 

beneath the floor and walls, which it is prob- 
able were formerly as numerous as they now 
are, had not collapsed in the course of time 
in the manner formerly explained, the under- 
lying earth would have been riddled with pas- 
sages like a sponge ; and as this was not 
the case, we may feel sure that they have 
collapsed. The inevitable result of such col- 
lapsing during successive centuries, will have 
been the slow subsidence of the floor and of the 
walls, and their burial beneath the accumu- 
lated worm-castings. The subsidence of a 
floor, whilst it still remains nearly horizontal,, 
may at first appear improbable ; but the case 
presents no more real difficulty than that of 
loose objects strewed on the surface of a field, 
which, as we have seen, become buried several 
inches beneath the surface in the course of a 
few years, though still forming a horizontal 
layer parallel to the surface. The burial of 
the paved and level path on my lawn, which 
took place under my own observation, is an 
analogous case. Even those parts of the- 
coricrete floor which the worms could not 
penetrate would almost certainly have been 
undermined, and would have sunk, like the great 



CHAP. IV. OF ANCIENT BUILDINGS. 193- 

stones at Leith Hill Place and Stonehenge, 
for the soil would have been damp beneath- 
them. But the rate of sinking of the dif- 
ferent parts would not have been quite equal, 
and the floor was not quite level. The 
foundations of the boundary walls lie, as 
shown in the section, at a very small depth 
beneath the surface ; they would therefore 
have tended to subside at nearly the same 
rate as the floor. But this would not have 
occurred if the foundations had been deep, 
as in the case of some other Roman ruins 
presently to be described. 

Finally, we may infer that a large part of 
the fine vegetable mould, which covered the 
floor and the broken-down walls of this villa, 
in some places to a thickness of 16 inches, 
was brought up from below by worms. From 
facts hereafter to be given there can be no' 
doubt that some of the finest earth thus 
brought up will have been washed down the 
sloping surface of the field during every heavy 
shower of rain. If this had not occurred a 
greater amount of mould would have accumu- 
lated over the ruins than that now present. 
But beside the castings of worms and some 



194 BURIAL OP THE REMAINS CHAP. IV. 

earth brought up by insects, and some accu- 
mulation of dust, much fine earth will have 
been washed over the ruins from the upper 
parts of the field, since it has been under 
cultivation ; and from over the ruins to the 
lower parts of the slope ; the present thick- 
ness of the mould being the resultant of these 
several agencies. 

I may here append a modern instance of 
the sinking of a pavement, communicated to 
me in 1871 by Mr. Ramsay, Director of the 
Geological Survey of England. A passage 
without a roof, 7 feet in length by 3 feet 2 
inches in width, led from his house into the 
garden, and was paved with slabs of Portland 
stone. Several of these slabs were 16 inches 
square, others larger, and some a little smaller. 
This pavement had subsided about 3 inches 
along the middle of the passage, and two 
inches on each side, as could be seen by the 
lines of cement by which the slabs had been 
originally joined to the walls. The pave- 
ment had thus become slightly concave along 
the middle; but there was no subsidence at 
the end close to the house. Mr. Ramsay 



CHAP. IV OF ANCIENT BUILDINGS. 195 

could not account for this sinking, until he 
observed that castings of black mould were 
frequently ejected along the lines of junction 
between the slabs ; and these castings were 
regularly swept away. The several lines of 
junction, including those with the lateral 
walls, were altogether 39 feet 2 inches in 
length. The pavement did not present the- 
appearance of ever having been renewed, 
and the house was believed to have been 
built about eighty-seven years ago. Con- 
sidering all these circumstances, Mr. Ramsay 
does not doubt that the earth brought up by 
the worms since the pavement was first laid 
down, or rather since the decay of the mortar 
allowed the worms to burrow through it, and 
therefore within a much shorter time than 
the eighty-seven years, has sufficed to cause the 
sinking of the pavement to the above amount, 
except close to the house, where the ground 
beneath would have been kept nearly dry. 

Beaulieu Abbey, Hampshire. This abbey 
was destroyed by Henry VIII., and there 
now remains only a portion of the southern 
aisle-wall. It is believed that the king had 
most of the stones carried away for building 

p 



196 BURIAL OF THE REMAINS CHAP. IV. 

a castle ; and it is certain that they have been 
removed. The positions of the nave and tran- 
septs were ascertained not long ago by the 
foundations having been found ; and the 
place is now marked by stones let into 
the ground. Where the abbey formerly 
stood, there now extends a smooth grass- 
covered surface, which resembles in all 
respects the rest of the field. The guardian, 
a very old man, said the surface had never 
been levelled in his time. In the year 1853, 
the Duke of Buccleuch had three holes dug 
in the turf within a few yards of one another, 
at the western end of the nave ; and the old 
tesselated pavement of the abbey was thus 
discovered. These holes were afterwards 
surrounded by brickwork, and protected by 
trap-doors, so that the pavement might be 
readily inspected and preserved. When my 
son William examined the place on January 
5, 1872, he found that the pavement in the 
three holes lay at depths of 6|, 10 and Hi 
inches beneath the surrounding turf-covered 
surface. The old guardian asserted that he 
was often forced to remove worm-castings 
from the pavement; and that he had done 



CHAP. IV. OF ANCIENT BUILDINGS. 197 

so about six months before. My son collected 
all from one of the holes, the area of which 
was 5-32 square feet, and they weighed 7*97 
ounces. Assuming that this amount had 
accumulated in six months, the accumulation 
during a year on a square yard would be 
1*68 pounds, which, though a large amount, 
is very small compared with what, as we 
have seen, is often ejected on fields and 
commons. When I visited the abbey on 
June 22, 1877, the old man said that he had 
cleared out the holes about a month before, 
but a good many castings had since been 
ejected. I suspect that he imagined that he 
swept the pavements oftener than he really 
did, for the conditions were in several re- 
spects very unfavourable for the accumulation 
of even a moderate amount of castings. The 
tiles are rather large, viz., about 5i inches 
square, and the mortar between them was in 
most places sound, so that the worms were 
able to bring up earth from below only at 
certain points. The tiles rested on a bed of 
concrete, and the castings in consequence con- 
sisted in large part (viz., in the proportion 
of 19 to 33) of particles of mortar, grains of 

p 2 



198 BUEIAL OF THE REMAINS CHAP. IV. 

sand, little fragments of rock, bricks or tile ; 
and such substances could hardly be agreeable, 
and certainly not nutritious, to worms. 

My son dug holes in several places within 
the former walls of the abbey, at a distance of 
several yards from the above described 
bricked squares. He did not find any tiles, 
though these are known to occur in some 
other parts, but he came in one spot to con- 
crete on which tiles had once rested. The 
fine mould beneath the turf on the sides of 
the several holes, varied in thickness from 
only 2 to 2 1 inches, and this rested on a layer 
from 8| to above 11 inches in thickness, 
consisting of fragments of mortar and stone- 
rubbish with the interstices compactly filled 
up with black mould. In the surrounding 
field, at a distance of 20 yards from the 
abbey, the fine vegetable mould was 11 inches 
thick. 

We may conclude from these facts that 
when the abbey was destroyed and the stones 
removed, a layer of rubbish was left over the 
whole surface, and that as soon as the worms 
were able to penetrate the decayed concrete 
and the joints between the tiles, they slowly 



CHAP. IV. OF ANCIENT BUILDINGS. 199 

filled up the interstices in the overlying 
rubbish with their castings, which were after- 
wards accumulated to a thickness of nearly 
three inches over the whole surface. If we 
add to this latter amount the mould between 
the fragments of stones, some five or six 
inches of mould must have been brought up 
from beneath the concrete or tiles. The con- 
crete or tiles will consequently have subsided 
to nearly this amount. The bases of the 
columns of the aisles are now buried beneath 
mould and turf. It is not probable that 
they can have been undermined by worms, 
for their foundations would no doubt have 
been laid at a considerable depth. If they 
have not subsided, the stones of which the 
columns were constructed must have been 
removed from beneath the former level of 
the floor. 

Chedworth, Gloucestershire. The remains 
of a large Roman villa were discovered here 
in 1866, on ground which had been covered 
with wood from time immemorial. No 
suspicion seems ever to have been enter- 
tained that ancient buildings lay buried here, 
until a gamekeeper, in digging for rabbits, 






200 BURIAL OF THE REMAINS CHAP. IY. 

encountered some remains.* But subse- 
quently the tops of some stone walls were de- 
tected in parts of the wood, projecting a little 
above the surface of the ground. Most of the 
coins found here belonged to Constans (who 
died 350 A.D.) and the Constantine family. 
My sons Francis and Horace visited the 
place in November 1877, for the sake of 
ascertaining what part worms may have 
played in the burial of these extensive re- 
mains. But the circumstances were not 
favourable for this object, as the ruins are sur- 
rounded on three sides by rather steep banks, 
down which earth is washed during rainy 
weather. Moreover most of the old rooms 
have been covered with roofs, for the pro- 
tection of the elegant tesselated pavements. 

A few facts may, however, be given on the 
thickness of the soil over these ruins. Close 
outside the northern rooms there is a broken 
wall, the summit of which was covered by 5 

* Several accounts of these ruins have been published ; the 
best is by Mr. James Farrer in ' Proc. Soc. of Antiquaries of 
Scotland,' vol. vi., Part II., 1867, p. 278. Also J. W. Grover, 
'Journal of the British Arch. Assoc.' June 1866. Professor 
Buckman has likewise published a pamphlet, 'Notes on the 
Roman Villa at Chedworth,' 2nd edit. 1873 : Cirencester. 



CHAP. IV. OP ANCIENT BUILDINGS. 201 

inches of black mould ; and in a hole dug on 
the outer side of this wall, where the ground 
had never before been disturbed, black mould, 
full of stones, 26 inches in thickness, was 
found, resting on the undisturbed sub-soil of 
yellow clay. At a depth of 22 inches from 
the surface a pig's jaw and a fragment of a 
tile were found. When the excavations were 
first made, some large trees grew over the 
ruins; and the stump of one has been left 
directly over a party-wall near the bath room, 
for the sake of showing the thickness of the 
superincumbent soil, which was here 38 
inches. In one small room, which, after 
being cleared out, had not been roofed over, 
my sons observed the hole of a worm passing 
through the rotten concrete, and a living 
worm was found within the concrete. In 
another open room worm-castings were seen 
on the floor, over which some earth had by 
this means been deposited, and here grass 
now grew. 

Brading, Isle of Wight. A fine Eoman 
villa was discovered here in 1880 ; and by 
the end of October no less than 18 chambers 
had been more or less cleared. A coin dated 



202 BURIAL OF THE REMAINS CHAP. IV. 

337 A.D. was found. My son William visited 
the place before the excavations were com- 
pleted ; and he informs me that most of the 
floors were at first covered with much rubbish 
and fallen stones, having their interstices 
completely filled up with mould, abounding, 
as the workmen said, with worms, above 
which there was mould without any stones. 
The whole mass was in most places from 3 
to above 4 ft. in thickness. In one very 
large room the overlying earth was only 
2 ft. 6 in. thick ; and after this had been re- 
moved, so many castings were thrown up 
between the tiles that the surface had to 
be almost daily swept. Most of the floors 
were fairly level. The tops of the broken- 
down walls were covered in some places by 
only 4 or 5 inches of soil, so that they were 
occasionally struck by the plough, but in 
other places they were covered by from 13 
to 18 inches of soil. It is not probable that 
these walls could have been undermined by 
worms and subsided, as they rested on a 
foundation of very hard red sand, into which 
worms could hardly burrow. The mortar, 
however, between the stones of the walls of 



CHAP. IV. OF ANCIENT BUILDINGS. 203 

a hypocaust was found by my son to have 
been penetrated by many worm-burrows. 
The remains of this villa stand on land which 
slopes at an angle of about 3 ; and the land 
appears to have been long cultivated. There- 
fore no doubt a considerable quantity of fine 
earth has been washed down from the upper 
parts of the field, and has largely aided in 
the burial of these remains. 

Silchester, Hampshire. The ruins of this 
small Roman town have been better pre- 
served than any other remains of the kind 
in England. A broken wall, in most parts 
from 15 to 18 feet in height and about Ij 
mile in compass, now surrounds a space of 
about 100 acres of cultivated land, on which 
a farm-house and a church stand.* Formerly, 
when the weather was dry, the lines of the 
buried walls could be traced by the appear- 
ance of the crops ; and recently very exten- 
sive excavations have been undertaken by 
the Duke of Wellington, under the superin- 
tendence of the late Kev. J. Gr. Joyce, by 
which means many large buildings have been 

* These details are taken from the 'Penny Cyclopaedia,' 
article Hampshire. 



204 BURIAL OF THE REMAINS CHAP. IV. 

discovered. Mr. Joyce made careful coloured 
sections, and measured the thickness of each 
bed of rubbish, whilst the excavations were in 
progress ; and he has had the kindness to 
send me copies of several of them. When 
my sons Francis and Horace visited these 
ruins, he accompanied them, and added his 
notes to theirs. 

Mr. Joyce estimates that the town was in- 
habited by the Eomans for about three cen- 
turies ; and no doubt much matter must have 
accumulated within the walls during this long 
period. It appears to have been destroyed 
by fire, and most of the stones used in the 
buildings have since been carried away. 
These circumstances are unfavourable for as- 
certaining the part which worms have played 
in the burial of the ruins; but as careful 
sections of the rubbish overlying an ancient 
town have seldom or never before been made 
in England, I will give copies of the most 
characteristic portions of some of those made 
by Mr. Joyce. They are of too great length 
to be here introduced entire. 

An east and west section, 30 ft. in length, 
was made across a room in the Basilica, now 



CHAP. IV. 



OF ANCIENT BUILDINGS. 



205 



called the Hall of the Merchants (Fig. 9). 
The hard concrete floor, still covered here 
and there with tesserae, was found at 3 ft. 




Fig. 9. 
Section within a room in the Basilica at Silchester. 



Scale 



206 BUEIAL OF THE EEMAINS CHAP. IV. 

beneath the surface of the field, which was 
here level. On the floor there were two 
large piles of charred wood, one alone of 
which is shown in the part of the section 
here given. This pile was covered by a thin 
white layer of decayed stucco or plaster, 
above which was a mass, presenting a singu- 
larly disturbed appearance, of broken tiles, 
mortar, rubbish and fine gravel, together 2*7 
inches in thickness. Mr. Joyce believes that 
the gravel was used in making the mortar 
or concrete, which has since decayed, some 
of the lime probably having been dissolved. 
The disturbed state of the rubbish may have 
been due to its having been searched for 
building stones. This bed was capped by 
fine vegetable mould, 9 inches in thickness. 
From these facts we may conclude that the 
Hall was burnt down, and that much rubbish 
fell on the floor, through and from which the 
worms slowly brought up the mould, now 
forming the surface of the level field. 

A section across the middle of another hall 
in the Basilica, 32 feet 6 inches in length, 
called the ^Erarium, is shown in Fig. 10. 
It appears that we have here evidence of two 



CHAP. IY. 



OF ANCIENT BUILDINGS. 



207 



fires, separated by an interval of time, during 
which the 6 inches of " mortar and concrete 




Fig. 10. 
Section within a hall in the Basilica at Silchester. Scale Jj. 



208 BURIAL OF THE REMAINS CHAP. IV 

with broken tiles " was accumulated. Be- 
neath one of the layers of charred wood, a 
valuable relic, a bronze eagle, was found; 
and this shows that the soldiers must have 
deserted the place in a panic. Owing to the 
death of Mr. Joyce, I have not been able to 
ascertain beneath which of the two layers the 
eagle was found. The bed of rubble overly- 
ing the undisturbed gravel originally formed, 
as I suppose, the floor, for it stands on a level 
with that of a corridor, outside the walls of 
the Hall; but the corridor is not shown in the 
section as here given. The vegetable mould 
was 16 inches thick in the thickest part; and 
the depth from the surface of the field, clothed 
with herbage, to the undisturbed gravel, was 
40 inches. 

The section shown in Fig. 11 represents an 
excavation made in the middle of the town, 
and is here introduced because the bed of " rich 
"mould" attained, according to Mr. Joyce, the 
unusual thickness of 20 inches. Gravel lay 
at the depth of 48 inches from the surface ; 
but it was not ascertained whether this was 
in its natural state, or had been brought here 
and had been rammed down, as occurs in 
f-ome other places. 



CHAP. IV. OF ANCIENT BUILDINGS. 209 

The section shown in Fig. 12 was taken 
in the centre of the Basilica, and though it was 
5 feet in depth, the natural sub-soil was not 




Mould, 20 inches 
thick. 



Rubble with broken 
tiles, 4 inches thick. 



Black decayed wood, 
in thickest part 6 
inches thick. 



Section in a block of buildings in the middle of the town of 
Silchester. 

reached. The bed marked " concrete " was 
probably at one time a floor; and the beds 
beneath seem to be the remnants of more 
ancient buildings. The vegetable mould was 



210 



BURIAL OF THE EEMAINS CHAP. IV. 



here only 9 inches thick, 
sections, not copied, we 




In some other 
likewise have 



Mould, 9 inches thick. 



Light -coloured earth with 
large pieces of broken 
" tiles, 7 inches. 



Dark, fine-grained rubbish 
with small bits of tiles, 
20 inches. 



Concrete, 4 inches. 
Stucco, 2 inches. 



Made bottom with frag- 
ments of tiles, 8 inches. 



ne-grained made ground, 
with the debris of older 
buildings. 



Fig. 12. 
Section in the centre of the Basilica at Silchester. 

evidence of buildings having been erected 
over the ruins of older ones. In one case 



CHAP. IV. OF ANCIENT BUILDINGS. 211 

there was a layer of yellow clay of very 
unequal thickness between two beds of debris, 
the lower one of which rested on a floor with 
tesserae. The ancient broken walls appear to 
have been sometimes roughly cut down to a 
uniform level, so as to serve as the founda- 
tions for a temporary building ; and Mr. Joyce 
suspects that some of these buildings were 
wattled sheds, plastered with clay, which 
would account for the above-mentioned layer 
of clay. 

Turning now to the points which more 
immediately concern us. Worm-castings 
were observed on the floors of several of the 
rooms, in one of which the tesselation was 
unusually perfect. The tesserae here con- 
sisted of little cubes of hard sandstone of 
about 1 inch, several of which were loose 
or projected slightly above the general level. 
One or occasionally two open worm-burrows 
were found beneath all the loose tesserae. 
Worms have also penetrated the old walls of 
these ruins. A wall, which had just been 
exposed to view during the excavations then 
in progress, was examined ; it was built of 
large flints, and was 18 inches in thickness. 

Q 



212 BURIAL OF THE REMAINS CHAP. IV. 

it appeared sound, but when the soil was 
removed from beneath, the mortar in the 
lower part was found to be so much decayed 
that the flints fell apart from their own 
weight. Here, in the middle of the wall, at 
a depth of 29 inches beneath the old floor and 
of 49 J inches beneath the surface of the field, 
a living worm was found, and the mortar was 
penetrated by several burrows. 

A second wall was exposed to view for the 
first time, and an open burrow was seen on 
its broken summit. By separating the flints 
this burrow was traced far down in the 
interior of the wall ; but as some of the flints 
cohered firmly, the whole mass was disturbed 
in pulling down the wall, and the burrow 
could not be traced to the bottom. The 
foundations of a third wall, which appeared 
quite sound, lay at a depth of 4 feet beneath 
one of the floors, and of course at a con- 
siderably greater depth beneath the level of 
the ground. A large flint was wrenched out 
of the wall at about a foot from the base, 
and this required much force, as the mortar 
was sound ; but behind the flint in the 
middle of the wall, the mortar was friable, 



CHAP. IV. OF ANCIENT BUILDINGS. 213 

and here there were worm-burrows. Mr. 
Joyce and my sons were surprised at the 
blackness of the mortar in this and in several 
other cases, and at the presence of mould in 
the interior cf the walls. Some may have 
been placed there by the old builders instead 
of mortar ; but we should remember that 
worms line their burrows with black humus. 
Moreover open spaces would almost certainly 
have been occasionally left between the large 
irregular flints ; and these spaces, we may 
feel sure, would be filled up by the worms 
with their castings, as soon as they were able 
to penetrate the wall. Eain-water, oozing 
down the burrows would also carry fine 
dark-coloured particles into every crevice. 
Mr. Joyce was at first very sceptical about 
the amount of work which I attributed to 
worms ; but he ends his notes with reference 
to the last-mentioned wall by saying, " This 
" case caused me more surprise and brought 
" more conviction to me than any other. I 
"should have said, and did say, that it was 
" quite impossible such a wa]l could have beer 
" penetrated by earth-worms." 

In almost all the rooms the pavement has 

Q 2 



214 



BURIAL OF THE REMAINS CHAP. IV. 





i 



I 

2 I 



sunk considerably, especi- 
ally towards the middle; 
and this is shown in the 
three following sections. 
The measurements were 
made by stretching a string 
tightly and horizontally 
over the floor. The sec- 
tion, Fig. 13, was taken 
from north to south across 
a room, 18 feet 4 inches in 
length, with a nearly per- 
fect pavement, next to the 
"Bed Wooden Hut." In 
the northern half, the sub- 
sidence amounted to 5f 
inches beneath the level of 
the floor as it now stands 
close to the walls; arid it 
was greater in the northern 
than in the southern half ; 
but, according to Mr. Joyce, 
the entire pavement has 
obviously subsided. In 
several places, the tesserae 
appeared as if drawn a little 
away from the walls ; whilst 



CHAP. IV OF ANCIENT BUILDINGS. 215 

in other places they were still in close contact 
with them. 

In Fig. 14, we see a section across the 
paved floor of the southern corridor or 
ambulatory of a quadrangle, in an excavation 
made near "The Spring." The floor is 7 
feet 9 inches wide, and the broken-down 
walls now project only f of an inch above its 
level. The field, which was in pasture, here 
sloped from north to south, at an angle 
of 3 40'. The nature of the ground at some 
little distance on each side of the corridor is 
shown in the section. It consisted of earth 
full of stones and other debris, capped with 
dark vegetable mould which was thicker on 
the lower or southern than on the northern 
side. The pavement was nearly level along 
lines parallel to the side-walls, but had sunk 
in the middle as much as 7f inches. 

A small room at no great distance from that 
represented in Fig. 13, had been enlarged by 
the Eoman occupier on the southern side, by 
an addition of 5 feet 4 inches in breadth. For 
this purpose the southern wall of the house had 
been pulled down, but the foundations of the 
old wall had been left buried at a little depth 



216 



BURIAL OF THE REMAINS CHAP. IV, 




CHAP. IV. OF ANCIENT BUILDINGS. 217 

beneath the pavement of the enlarged room. 
Mr. Joyce believes that this buried wall must 
have been built before the reign of Claudius II., 
who died 270 A.D. We see in the accom- 
panying section, Fig. 15, that the tesselated 
pavement has subsided to a less degree over the 
buried wall than elsewhere ; so that a slight 
convexity or protuberance here stretched in a 
straight line across the room. This led to 
a hole being dug, and the buried wall was 
thus discovered. 

We see in these three sections, and in 
several others not given, that the old pave- 
ments have sunk or sagged considerably. 
Mr. Joyce formerly attributed this sinking 
solely to the slow settling of the ground. 
That there has been some settling is highly 
probable, and it may be seen in Fig. 15 
that the pavement for a width of 5 feet 
over the southern enlargement of the 
room, which must have been built on fresh 
ground, has sunk a little more than on the 
old northern side. But this sinking may 
possibly have had no connection with the 
enlargement of the room; for in Fig. 13 
one half of the pavement has subsided more 



218 BURIAL OF THE REMAINS CHAP. IV 




1 



CHAP. TV OF ANCIENT BUILDINGS. 219 

than the other half without any assignable 
cause. In a bricked passage to Mr. Joyce's 
own house, laid down only about six years 
ago, the same kind of sinking has occurred as 
in the ancient buildings. Nevertheless it does 
not appear probable that the whole .amount 
of sinking can be thus accounted for. The 
Roman builders excavated the ground to an 
unusual depth for the foundations of their 
walls, which were thick and solid ; it is 
therefore hardly credible that they should 
have been careless about the solidity of the 
bed on which their tesselated and often 
ornamented pavements were laid. The sink- 
ing must, as it appears to me, be attributed 
in chief part to the pavement having been 
undermined by worms, which we know are 
still at work. Even Mr. Joyce at last ad- 
mitted that this could not have failed to have 
produced a considerable effect. Thus also the 
large quantity of fine mould overlying the 
pavements can be accounted for, the presence 
of which would otherwise be inexplicable. My 
sons noticed that in one room in which the 
pavement had sagged very little, there was an 
unusually small amount of overlying mould. 



220 BURIAL OP THE REMAINS CHAP. IV. 

As the foundations of the walls generally 
lie at a considerable depth, they will either 
have not subsided at all through the under- 
mining action of worms, or they will have 
subsided much less than the floor. This 
latter result would follow from worms not 
often working deep down beneath the founda- 
tions ; but more especially from the walls not 
yielding when penetrated by worms, whereas 
the successively formed burrows in a mass 
of earth, equal to one of the walls in depth 
and thickness, would have collapsed many 
times since the desertion of the ruins, 
and would consequently have shrunk or 
subsided. As the walls cannot have sunk 
much or at all, the immediately adjoining 
pavement from adhering to them will have 
been prevented from subsiding; and thus 
the present curvature of the pavement i* 
intelligible. 

The circumstance which has surprised me 
most with respect to Silchester is that during 
the many centuries which have elapsed since 
the old buildings were deserted, the vegetable 
mould has not accumulated over them to a 
greater thickness than that here observed. In 






CHAP.V. OF ANCIENT BUILDINGS. 221 

most places it is only about 9 inches in thick- 
ness, but in some places 12 or even more 
inches. In Fig. 11, it is given as 20 inches, 
but this section was drawn by Mr. Joyce 
before his attention was particularly called to 
this subject. The land enclosed within the 
old walls is described as sloping slightly to 
the south ; but there are parts which, accord- 
ing to Mr. Joyce, are nearly level, and it 
appears that the mould is here generally 
thicker than elsewhere. The surface slopes 
in other parts from west to east, and Mr. Joyce 
describes one floor as covered at the western 
end by rubbish and mould to a thickness 
of 28^ inches, and at the eastern end by a 
thickness of only 11 J inches. A very slight 
slope suffices to cause recent castings to flow 
downwards during heavy rain, and thus much 
earth will ultimately reach the neighbouring 
rills and streams and be carried away. By 
this means, the absence of very thick beds of 
mould over these ancient rrains may, as I 
believe, be explained. Moreover most of the 
land here has long been ploughed, and this 
would greatly aid the washing away of the 
finer earth during rainy weather. 



222 BUEIAL OF THE BEMAINS CHAP. IV. 

The nature of the beds immediately 
beneath the vegetable mould in some of the 
sections is rather perplexing. We see, for 
instance, in the section of an excavation in a 
grass meadow (Fig. 14), which sloped from 
north to south at an angle of 3 40', that the 
mould on the upper side is only six inches 
and on the lower side nine inches in thick- 
ness. But this mould lies on a mass (25 J 
inches in thickness on the upper side) " of 
"dark brown mould," as described by Mr. 
Joyce, " thickly interspersed with small 
" pebbles and bits of tiles, which present a 
"corroded or worn appearance." The state 
of this dark-coloured earth is like that of a 
field which has long been ploughed, for the 
earth thus becomes intermingled with stones 
and fragments of all kinds which have been 
much exposed to the weather. If during the 
course of many centuries this grass meadow 
and the other now cultivated fields have been 
at times ploughed, and at other times left as 
pasture, the nature of the ground in the above 
section is rendered intelligible. For worms 
will continually have brought up fine earth 
from below, which will have been stirred 



CHAP. IV. OF ANCIENT BUILDINGS. 223 

up by the plough whenever the land was 
cultivated. But after a time a greater 
thickness of fine earth will thus have been 
accumulated than could be reached by the 
plough; and a bed like the 25^-inch mass, 
in Fig. 14, will have been formed beneath 
the superficial mould, which latter will have 
been brought to the surface within more 
recent times, and have been well sifted by 
the worms. 

Wrosseter, Shropshire. The old Roman city 
of Uriconium was founded in the early part 
of the second century, if not before this date ; 
and it was destroyed, according to Mr. 
Wright, probably between the middle of the 
fourth and fifth century. The inhabitants 
were massacred, and skeletons of women 
were found in the hypocausts. Before the 
year 1859, the sole remnant of the city above 
ground, was a portion of a massive wall 
about 20 ft. in height. The surrounding 
land undulates slightly, and has long been 
under cultivation. It had been noticed that 
the corn-crops ripened prematurely in certain 
narrow lines, and that the snow remained un- 
melted in certain places longer than in others. 



224 BURIAL OF THE REMAINS CHAP. IV. 

These appearances led, as I was informed, to 
extensive excavations being undertaken. The 
foundations of many large buildings and 
several streets have thus been exposed to view. 
The space enclosed within the old walls is 
an irregular oval, about 1| mile in length. 
Many of the stones or bricks used in the 
buildings must have been carried away ; but 
the hypocausts, baths, and other underground 
buildings were found tolerably perfect, being 
filled with stones, broken tiles, rubbish and 
soil. The old floors of various rooms were 
covered with rubble. As I was anxious to 
know how thick the mantle of mould and 
rubbish was, which had so long concealed 
these ruins, I applied to Dr. H. Johnson, who 
had superintended the excavations ; and he, 
with the greatest kindness, twice visited the 
place to examine it in reference to my ques- 
tions, and had many trenches dug in four 
fields which had hitherto been undisturbed. 
The results of his observations are given in 
the following Table. He also sent me speci- 
mens of the mould, and answered, as far as 
he could, all my questions. 



CHAP. IV. OF ANCIENT BUILDINGS. 225 



MEASUREMENTS BY DB. H. JOHKSON OF THE THICKNESS OF 
THE VEGETABLE MOULD OVEB THE ROMAN BUIN8 AT 
WBOXETER. 

Trenches dug in a field called " Old Works." 

Thickness 

of mould in 

inches. 

1. At a depth of 36 inches undisturbed sand was 

reached 20 

2. At a depth of 33 inches concrete was reached 21 

3. 9 inches concrete was reached 9 

Trenches dug in a field called "Shop 
Leasows ;" this is the highest field within the 
old walls, and slopes down from a sub-central 
point on all sides at about an angle of 2. 



of mould in 
inches. 

4. Summit of field, trench 45 inches deep . . 40 

5. Close to summit of field, trench 36 inches deep 26 

6. trench 28 inches deep 28 

7. Near summit of field, trench 36 inches deep 24 

8. trench at. one end 39 
inches deep ; the mould here graduated into 
the underlying undisturbed sand, and its 
thickness (24 inches) is somewhat arbitrary. 
At the other end of the trench, a causeway 
was encountered at a depth of only 7 inches, 
and the mould was here only 7 inches thick 24 

9. Trench close to the last, 28 inches in depth .. 15 

10. Lower part of same field, trench 30 inches deep 15 

11. trench 31 inches deep 17 

12. trench 36 inches deep, 

at which depth undisturbed sand was reached 28 



226 BURIAL OF THE REMAINS CHAP. IV. 

Thickness 

of mould in 

inches. 

13. In another part of same field, trench 9 inches 

deep, stopped by concrete 9i 

14. In another part of same field, trench 9 inches 

deep, stopped by concrete .. .. .. 9 

15. In another part of the same field, trench 24 

inches deep, when sand was reached .. 16 

16. In another part of same field, trench 30 inches 

deep, when stones were reached ; at one end 
of the trench mould 12 inches, at the other 
end 14 inches thick 13 

Small field between "Old Works" and 
" Shop Leasows," I believe nearly as high as 
the upper part of the latter field. 

Thickness 

of mould in 

inches. 

17. Trench 26 inches' deep 24 

18. 10 inches deep, and then came upon a 
causeway 10 

19. Trench 34 inches deep 30 

20. 31 inches deep 31 

Field on the western side of the space 
enclosed within the old walls. 

Thickness 

of mould in 

inches. 

21. Trench 28 inches deep, when undisturbed sand 

was reached .. .. .. .. ..16 

22. Trench 29 inches deep, when undisturbed sand 

was reached .. .. .. .. .. 15 

23. Trench 14 inches deep, and then came upon a 

building .. .. .. .. .. 14 

Dr. Johnson distinguished as mould the 
earth which differed, more or less abruptly, in 



CHAP. IV. OF ANCIENT BUILDINGS. 22T 

its dark colour and in its texture from the 1 
underlying sand or rubble. In the specimen* 
sent to me, the mould resembled that which 
lies immediately beneath the turf in old 
pasture-land, excepting that it often contained 
small stones, too large to have passed through 
the bodies of worms. But the trenches above- 
described were dug in fields, none of which 
were in pasture, and all had been long 
cultivated. Bearing in mind the remarks 
made in reference to Silchester on the effects 
of long-continued culture, combined with the 
action of worms in bringing up the finer 
particles to the surface, the mould, as so- 
designated by Dr. Johnson, seems fairly well 
to deserve its name. Its thickness, where 
there was no causeway, floor or walls beneath,, 
was greater than has been elsewhere ob- 
served, namely, in many places above 2 ft,. 
and in one spot above 3 ft. The mould was 
thickest on and close to the nearly level sum- 
mit of the field called " Shop Leasows," and 
in a small adjoining field, which, as I believe, 
is of nearly the same height. One side of 
the former field slopes at an angle of rather 
above 2, and I should have expected that 

R 



228 BUKIAL OF THE KEMAINS CHAP. IV. 

the mould, from being washed down during 
heavy rain, would have been thicker in the 
lower than in the upper part; but this was 
not the case in two out of the three trenches 
here dug. 

In many places, where streets ran beneath 
the surface, or where old buildings stood, the 
mould was only 8 inches in thickness; and 
Dr. Johnson was surprised that in ploughing 
the land, the ruins had never been struck by 
the plough as far as he had heard. He thinks 
that when the land was first cultivated the old 
walls were perhaps intentionally pulled down, 
and that hollow places were filled up. This 
may have been the case; but if after the 
desertion of the city the land was left for 
many centuries uncultivated, worms would 
have brought up enough fine earth to have 
covered the ruins completely ; that is if 
they had subsided from having been under- 
mined. The foundations of some of the walls, 
for instance those of the portion still stand- 
ing about 20 feet above the ground, and 
those of the market-place, lie at the extra- 
ordinary depth of 14 feet; but it is highly 
improbable that the foundations were gener- 



CHAP. IV. OP ANCIENT BUILDINGS. 229 

ally so deep. The mortar employed in the 
buildings must have been excellent, for it 
is still in parts extremely hard. Wher- 
ever walls of any height have been exposed 
to view, they are, as Dr. Johnson believes, 
still perpendicular. The walls with such 
deep foundations cannot have been under- 
mined by worms, and therefore cannot have 
subsided, as appears to have occurred at 
Abinger and Silchester. Hence it is very 
difficult to account for their being now com- 
pletely covered with earth; but how much 
of this covering consists of vegetable mould 
and how much of rubble I do not know. 
The market-place, with the foundations at a 
depth of 14 feet, was covered up, as Dr. 
Johnson believes, by between 6 and 24 inches 
of earth. The tops of the broken-down walls 
of a caldarium or bath, 9 feet in depth, were 
likewise covered up with nearly 2 feet of 
earth. The summit of an arch, leading into 
an ash-pit 7 feet in depth, was covered up 
with not more than 8 inches of earth. When- 
ever a building which has not subsided is 
covered with earth, we must suppose, either 
that the upper layers of stone have been at 

R 2 



230 BUEIAL OF THE REMAINS CHAP. IV. 

some time carried away by man, or that earth 
has since been washed down during heavy 
rain, or blown down during storms, from the 
adjoining land ; and this would be especially 
apt to occur where the land has long been 
cultivated. In the above cases the adjoining 
land is somewhat higher than the three speci- 
fied sites, as far as I can judge by maps and 
from information given me by Dr. Johnson. 
If, however, a great pile of broken stones, 
mortar, plaster, timber and ashes fell over the- 
remains of any building, their disintegration 
in the course of time, and the sifting action 
of worms, would ultimately conceal the whole 
beneath fine earth. 

Conclusion. The cases given in this chapter 
show that worms have played a considerable 
part in the burial and concealment of several 
Roman and other old buildings in England ; 
but no doubt the washing down of soil from 
the neighbouring higher lands, and the de- 
position of dust, have together aided largely 
in the work of concealment. Dust would be 
apt to accumulate wherever old broken-down 
walls projected a little above the then exist- 



CHAP. IV. OF ANCIENT BUILDINGS. 231 

ing surface and thus afforded some shelter. 
The floors of the old rooms, halls and passages 
have generally sunk, partly from the settling 
of the ground, but chiefly from having been 
undermined by worms; and the sinking has 
commonly been greater in the middle than 
near the walls. The walls themselves, when- 
ever their foundations do not lie at a great 
depth, have been penetrated and undermined 
by worms, and have consequently subsided. 
The unequal subsidence thus caused, probably 
explains the great cracks which may be seen 
in many ancient walls, as well as their 
inclination from the perpendicular. 



232 DISINTEGRATION CHAP. V. 



CHAPTER Y. 

THE ACTION OF WORMS IN THE DENUDATION 
OP THE LAND. 

Evidence of the amount of denudation which the land has 
undergone Sub-aerial denudation The deposition of dust 
Vegetable mould, its dark colour and fine texture largely due 
to the action of worms The disintegration of rocks by the 
humus-acids Similar acids apparently generated within the 
bodies of worms The action of these acids facilitated by the 
continued movement of the particles of earth A thick bed of 
mould checks the disintegration of the underlying soil and 
rocks. Particles of stone worn or triturated in the gizzards of 
worms Swallowed stones serve as mill-stones The levi- 
gated state of the castings Fragments of brick in the castings 
over ancient buildings well rounded. The triturating power of 
worms not quite insignificant under a geological point of view. 

No one doubts that our world at one time 
consisted of crystalline rocks, and that it is to 
their disintegration through the action of air, 
water, changes of temperature, rivers, waves 
of the sea, earthquakes and volcanic outbursts, 
that we owe our sedimentary formations. 
These after being consolidated and sometimes 



CHAP. V. AND DENUDATION. 233 

recrystallized, have often 'been again dis- 
integrated. Denudation means the removal 
of such disintegrated matter to a lower level. 
Of the many striking results due to the 
modern progress of geology there are hardly 
any more striking than those which relate to 
denudation. It was long ago seen that 
there must have been an immense amount 
of denudation ; but until the successive forma- 
tions were carefully mapped and measured, 
no one fully realised how great was the 
amount. One of the first and most remark- 
able memoirs ever published on this subject 
was that by Ramsay,* who in 1846 showed 
that in Wales from 9000 to 11,000 feet in 
thickness of solid rock had been stripped off 
large tracks of country. Perhaps the plainest 
evidence of great denudation is afforded by 
faults or cracks, which extend for many miles 
across certain districts, with the strata on one 
side raised even ten thousand feet above the 
corresponding strata on the opposite side ; and 
yet there is not a vestige of this gigantic 
displacement visible on the surface of the 

* " On the denudation of South Wales," &c., Memoirs of the 
Geological Survey of Great Britain,' vol. i., p. 297, 134G 



2H4 DISINTEGRATION CHAP. V. 

land. A Luge pile of rock has been planed 
iiway on one side and not a remnant left. 

Until the last twenty or thirty years, most 
geologists thought that the waves of the sea 
were the chief agents in the work of denuda- 
tion ; but we may now feel sure that air and 
rain, aided by streams and rivers, are much 
more powerful agents, that is if we consider 
the whole area of the land. The long lines of 
escarpment which stretch across several parts 
of England were formerly considered to be 
undoubtedly ancient coast-lines ; but we now 
know that they stand up above the general 
surface merely from resisting air, rain and 
frost better than the adjoining formations. 
It has rarely been the good fortune of a 
geologist to bring conviction to the minds of 
his fellow- workers on a disputed point by a 
single memoir ; but Mr. Whitaker, of the 
Geological Survey of England, was so for- 
tunate when, in 1867, he published his paper 
" On sub-aerial Denudation, and on Cliffs and 
Escarpments of the Chalk." * Before this 

* 'Geological Magazine,' October and November, 18G7, vol. 
iv. pp. 447 and 483. Copious references on the subject are given 
in this remarkable memoir. 






CHAP. Y. AND DENUDATION. 235 

paper appeared, Mr. A. Tylor had adduced 
important evidence on sub-aerial denudation, 
by showing that the amount of matter 
brought down by rivers must infallibly lower 
the level of their drainage-basins by many 
feet in no immense lapse of time. This line 
of argument has since been followed up in the 
most interesting manner by Archibald Geikie, 
Croll and others, in a series of valuable 
memoirs.* For the sake of those who have 
never attended to this subject, a single 
instance may be here given, namely, that of 
the Mississippi, which is chosen because the 
amount of sediment brought down by this 
great river has been investigated with especial 
care by order of the United States Govern- 
ment. The result is, as Mr. Croll shows, that 
the mean level of its enormous area of 

* A. Tylor " On changes of the sea-level," &c., ' Philosophical 
Mag.' (Ser. 4th) vol. v., 1853, p. 258. Archibald Geikie, 
Transactions Geolog. Soc. of Glasgow, vol. iii., p. 153 (read March, 
1868). Croll "On Geological Time," 'Philosophical Mag.,' 
May, August, and November, 1868. See also Croll, * Climate 
and Time,' 1875, Chap. XX. For some recent information on 
the amount of sediment brought down by rivers, see ' Nature, 1 
Sept. 23rd, 1880. Mr. T. Mellard Reade has published some 
interesting articles on the astonishing amount of matter 
brought down in solution by rivers. See Address, Geolog. Soc., 
Liverpool, 1876-77. 



236 DISINTEGRATION CHAP. Y. 

drainage must be lowered 45 1 66 of a foot 
annually, or 1 foot in 4566 years. Con- 
sequently, taking the best estimate of the 
mean height of the North American continent, 
viz. 748 feet, and looking to the future, the 
whole of the great Mississippi basin will be 
washed away, and " brought down to the sea- 
" level in less than 4,500,000 years, if no 
" elevation of the land takes place." Some 
rivers carry down much more sediment re- 
latively to their size, and some much less than 
the Mississippi. 

Disintegrated matter is carried away by 
the wind as well as by running water.. 
During volcanic outbursts much rock is 
triturated and is thus widely dispersed; and 
in all arid countries the wind plays an im- 
portant part in the removal of such matter. 
Wind-driven sand also wears down the 
hardest rocks. I have shown* that during 
four months of the year a large quantity of 
dust is blown from the north-western shores 
of Africa, and falls on the Atlantic over a 

* " An account of the fine dust which often falls on Vessels ia 
the Atlantic Ocean," Proc. Geolog. Soc. of London, June 4th,. 
1845. 



CHAP. V. AND DENUDATION. 237 

space of 1600 miles in latitude, and for a 
distance of from 300 to 600 miles from the 
coast. But dust has been seen to fall at a 
distance of 1030 miles from the shores of 
Africa. During a stay of three weeks at 
St. Jago in the Cape Verde Archipelago, the 
atmosphere was almost always hazy, and ex- 
tremely fine dust coming from Africa was con- 
tinually falling. In some of this dust which 
fell in the open ocean at a distance of between 
330 and 380 miles from the African coast, there- 
were many particles of stone, about y^o of an 
inch square. Nearer to the coast the water 
has been seen to be so much discoloured by 
the falling dust, that a sailing vessel left a 
track behind her. In countries, like the Cape 
Verde Archipelago, where it seldom rains 
and there are no frosts, the solid rock never- 
theless disintegrates ; and in conformity with 
the views lately advanced by a distinguished 
Belgian geologist, De Koninck, such disin- 
tegration may be attributed in chief part to 
the action of the carbonic and nitric acids, 
together with the nitrates and nitrites of 
ammonia, dissolved in the dew. 

In all humid, even moderately humid, 



238 DISINTEGRATION CHAP. V. 

countries, worms aid in the work of denuda- 
tion in several ways. The vegetable mould 
which covers, as with a mantle, the surface 
of the land, has all passed many times 
through their bodies. Mould differs in ap- 
pearance from the subsoil only in its dark 
colour, and in the absence of fragments or 
particles of stone (when such are present in 
the subsoil), larger than those which can pass 
through the alimentary canal of a worm. 
This sifting of the soil is aided, as has already 
been remarked, by burrowing animals of 
many kinds, especially by ants. In countries 
where the summer is long and dry, the 
mould in protected places must be largely 
increased by dust blown from other and more 
exposed places. For instance, the quantity 
of dust sometimes blown over the plains of 
La Plata, where there are no solid rocks, is 
so great, that during the " gran seco," 1827 
to 1830, the appearance of the land, which 
is here unenclosed, was so completely changed 
that the inhabitants could not recognise the 
limits of their own estates, and endless law- 
suits arose. Immense quantities of dust are 
likewise blown about in Egypt and in the 



CHAP. V. AND DENUDATION. 23 

south of France. In China, as Bichthofcn 
maintains, beds appearing like fine sediment, 
several hundred feet in thickness and extend- 
ing over an enormous area, owe their origin 
to dust blown from the high lands of central 
Asia.* In humid countries like Great 
Britain, as long as the land remains in its 
natural state clothed with vegetation, the 
mould in any one place can hardly be much 
increased by dust ; but in its present con- 
dition, the fields near high roads, where there 
is much traffic, must receive a considerable 
amount of dust, and when fields are harrowed 
during dry and windy weather, clouds of dust 
may be seen to be blown away. But in all 
these cases the surface-soil is merely trans- 
ported from one place to another. The dust 
which falls so thickly within our houses con- 

* For La Plata, see my ' Journal of Researches,' during the 
voyage of the Beagle, 1845, p. 133. Elie de Beaumont has 
given (' Lecons de Geolog. pratique,' torn. 1. 1845, p. 183) an 
excellent account of the enormous quantity of dust which is 
transported in some countries. I cannot but think that Mr. 
Proctor has somewhat exaggerated (' Pleasant Ways in Science,' 
1879, p. 379) the agency of dust in a humid country like Great 
Britain. James Geikie has given (' Prehistoric Europe,' 1880, 
p. 165) a full abstract of Richthofen's views, which, however, 
he disputes, 



"240 DISINTEGRATION CHAP. V. 

sists largely of organic matter, and if spread 
over the land would in time decay and dis- 
appear almost entirely. It appears, however, 
from recent observations on the snow-fields 
of the Arctic regions, that some little meteoric 
dust of extra mundane origin is continually 
falling. 

The dark colour of ordinary mould is 
obviously due to the presence of decaying 
organic matter, which, however, is present in 
but small quantities. The loss of weight 
which mould suffers when heated to redness 
seems to be in large part due to water in com- 
bination being dispelled. In one sample of 
fertile mould the amount of organic matter 
was ascertained to be only 1*76 per cent. ; in 
some artificially prepared soil it was as much 
as 5' 5 per cent., and in the famous black soil of 
Russia from 5 to even 12 per cent.* In leaf- 
mould formed exclusively by the decay of 
leaves the amount is much greater, and in 
peat the carbon alone sometimes amounts to 



* These statements are taken from Hensen in 'Zeitschrift 
fur wissenschaft. Zoologie' Bd. xxviii., 1877, p. 360. Those 
with respect to peat are taken from Mr. A. A. Julien in ' Proc. 
American Assoc. Science,' 1879 p. 314. 



CHAP. V. AND DENUDATION. 241 

64 per cent. ; but with these latter cases we 
are not here concerned. The carbon in the 
soil tends gradually to oxidise and to dis- 
appear, except where water accumulates and 
the climate is cool ; * so that in the oldest 
pasture-land there is no great excess of 
organic matter, notwithstanding the con- 
tinued decay of the roots and the underground 
stems of plants, and the occasional addition 
of manure. The disappearance of the organic 
matter from mould is probably much aided 
by its being brought again and again to the 
surface in the castings of worms. 

Worms, on the other hand, add largely to 
the organic matter in the soil by the astonish- 
ing number of half-decayed leaves which 
they draw into their burrows to a depth of 2 
or 3 inches. They do this chiefly for obtain- 
ing food, but partly for closing the mouths 
of their burrows and for lining the upper 
part. The leaves which they consume are 
moistened, torn into small shreds, partially 
digested, and intimately commingled with 

* I have given some facts on the climate necessary or favour* 
able for the formation of peat, in my * Journal of Researches,' 
1845, p. 287. 



242 DISINTEGRATION CHAP. Y. 

earth ; and it is this process which gives to 
vegetable mould its uniform dark tint. It is 
known that various kinds of acids are gene- 
rated by the decay of vegetable matter ; and 
from the contents of the intestines of worms and 
from their castings being acid, it seems pro- 
bable that the process of digestion induces an 
analogous chemical change in the swallowed, 
triturated, and half-decayed leaves. The large 
quantity of carbonate of lime secreted by the 
calciferous glands apparently serves to neutra- 
lise the acids thus generated ; for the digestive 
fluid of worms will not act unless it be alkaline. 
As the contents of the upper part of their in- 
testines are acid, the acidity can hardly be due 
to the presence of uric acid. We may there- 
fore conclude that the acids in the alimentary 
canal of worms are formed during the diges- 
tive process; and that probably they are 
nearly of the same nature as those in ordinary 
mould or humus. The latter are well known to 
have the power of de-oxidising or dissolving 
per-oxide of iron, as may be seen wherever 
peat overlies red sand, or where a rotten root 
penetrates such sand. Now I kept some 
worms in a pot filled with very fine reddish 



HAP. V. AND DENUDATION. 243 

sand, consisting of minute particles of silex 
coated with the red oxide of iron ; and the 
burrows, which the worms made through this 
sand, were lined or coated in the usual manner 
with their castings, formed of the sand mingled 
with their intestinal secretions and the refuse 
of the digested leaves; and this sand had 
almost wholly lost its red colour. When 
small portions of it were placed under the 
microscope, most of the grains were seen to 
be transparent and colourless, owing to the 
dissolution of the oxide ; whilst almost all the 
grains taken from other parts of the pot were 
coated with the oxide. Acetic acid produced 
hardly any effect on this sand ; and even 
hydrochloric, nitric and sulphuric acids, 
diluted as in the Pharmacopoeia, produced 
less effect than did the acids in the intestines 
of the worms. 

Mr. A. A. Julien has lately collected all 
the extant information about the acids gen- 
erated in humus, which, according to some 
chemists, amount to more than a dozen 
different kinds. These acids, as well as their 
acid salts (i.e., in combination with potash, 
soda, and ammonia), act energetically on 

8 



244 DISINTEGRATION CHAP. V, 

carbonate of lime and on the oxides of iron. 
It is also known that some of these acids,. 
which were called long ago by Thenard azo- 
humic, are enabled to dissolve colloid silica in 
proportion to the nitrogen which they contain.* 
In the formation of these latter acids worms 
probably afford some aid, for Dr. H. Johnson 
informs me that by Nessler's test he found, 
O'OIS per cent, of ammonia in their castings. 
It may be here added that I have recently 
been informed by Dr. Grilbert "that several 
" square yards on his lawn were swept clean, 
" and after two or three weeks all the worin- 
" castings on the space were collected and 
'* dried. These were found to contain 0'35 
*' of nitrogen. This is from two to three times 
" as much as we find in our ordinary arable 
" surface-soil ; more than in our ordinary 
" pasture surface-soil ; but less than in rich 
" kitchen-garden mould. Supposing a quantity 
"of castings equal to 10 tons in the dry 

* A. A. Julieu " On the Geological action of the Humus-acids," 
'Proc. American Assoc. Science,' vol. xxviii., 1879, p. 311. 
Also on " Chemical erosion on Mountain Summits ;" ' New York 
Academy of Sciences,' Oct. 14, 1878, as quoted in the ' American 
Naturalist.' See also, on this subject, S. W. Johnson, ' How 
Crops Feed,' 1870, p. 138. 



CHAP. V. AND DENUDATION. 245 

" state were annually deposited on an acre, 
" this would represent a manuring of 78 Ibs. 
" of nitrogen per acre per annum ; and this 
"is very much more than the amount of 
" nitrogen in the annual yield of hay per 
"acre, if raised without any nitrogenous 
" manure. Obviously, so far as the nitrogen 
"in the castings is derived from surface- 
" growth or from surface-soil, it is not a gain 
"to the latter; but so far as it is derived from 
" below, it is a gain." 

The several humus-acids, which appear, as 
we have just seen, to be generated within the 
bodies of worms during the digestive process, 
and their acid salts, play a highly important 
part, according to the recent observations of 
Mr. Julien, in the disintegration of various 
kinds of rocks. It has long been known that 
the carbonic acid, and no doubt nitric and 
nitrous acids, which are present in rain-water, 
act in like manner. There is, also, a great 
excess of carbonic acid in all soils, especially 
in rich soils, and this is dissolved by the water 
in the ground. The living roots of plants, 
moreover, as Sachs and others have shown, 
quickly corrode and leave their impressions 

s 2 



'246 DISINTEGKATION CHAP. V. 

on polished slabs of marble, dolomite and 
phosphate of lime. They will attack even 
basalt and sandstone.* But we are not here 
concerned with agencies which are wholly 
independent of the action of worms. 

The combination of any acid with a base 
is much facilitated by agitation, as fresh 
surfaces are thus continually brought into 
contact. This will be thoroughly effected 
with the particles of stone and earth in the 
intestines of worms, during the digestive pro- 
cess ; and it should be remembered that the 
entire mass of the mould over every field, 
passes, in the course of a few years, through 
their alimentary canals. Moreover as the old 
'burrows slowly collapse, and as fresh castings 
are continually brought to the surface, the 
whole superficial layer of mould slowly re- 
solves or circulates; and the friction of the 
particles one with another will rub off the 
finest films of disintegrated matter as soon as 
they are formed. Through these several 
means, minute fragments of rocks of many 

kinds and mere particles in the soil will be 



* See, for references on this subject, S. W. Johnson, ' How 
'Crops Feed, 1 1870, p. 326. 



CHAP. V. AND DENUDATION. 247' 

continually exposed to chemical decomposi- 
tion ; and thus the amount of soil will tend 
to increase. 

As worms line their burrows with their 
castings, and as the burrows penetrate to a- 
depth of 5 or G, or even more feet, some- 
small amount of the humus-acids will be- 
carried far down, and will there act on the- 
underlying rocks and fragments of rock, 
Thus the thickness of the soil, if none be re- 
moved from the surface, will steadily though 
slowly tend to increase ; but the accumulation 
will after a time delay the disintegration of" 
the underlying rocks and of the more deeply 
seated particles. For the humus-acids which 
are generated chiefly in the upper layer of 
vegetable mould, are extremely unstable com- 
pounds, and are liable to decomposition before 
they reach any considerable depth.* A thick" 
bed of overlying soil will also check the: 
downward extension of great fluctuations of 
temperature, and in cold countries will check 
the powerful action of frost. The free access 
of air will likewise be excluded. From these- 

* This statement is taken from Mr. Julien, ' Proc. American 
Assoc. Science,' vol. xxviii., 1879, p. 330. 



248 DISINTEGRATION CHAP. V. 

several causes disintegration would be almost 
arrested, if the overlying mould were to 
increase much in thickness, owing to none or 
little being removed from the surface.* In 
my own immediate neighbourhood we have a 
curious proof how effectually a few feet of 
clay checks some change which goes on in 
flints, lying freely exposed; for the large 
ones which have lain for some time on the 
surface of ploughed fields cannot be used for 
building ; they will not cleave properly and 
are said by the workmen to be rotten, f It is 
therefore necessary to obtain flints for build- 
ing purposes from the bed of red clay over- 

* The preservative power of a layer of mould and turf is often 
/hown by the perfect state of the glacial scratches on rocks when 
first uncovered. Mr. J. Geikie maintains, in his last very inter- 
esting work (' Prehistoric Europe,' 1881), that the more perfect 
scratches are probably due to the last access of cold and increase 
of ice, during the long-continued, intermittent glacial period. 

f Many geologists have felt much surprise at the complete 
disappearance of flints over wide and nearly level areas, from 
which the chalk has been removed by subaerial denudation. 
But the surface o every flint is coated by an opaque modified 
layer, which will just yield to a steel point, whilst the freshly- 
fractured, translucent surface will not thus yield. The re- 
moval by atmospheric agencies of the outer modified surfaces 
of freely exposed flints, though no doubt excessively slow, to- 
gether with the modification travelling inwards, will, as may be 
suspected, ultimately lead to their complete disintegration, not- 
withstanding that they appear to be so extremely durable. 



CHAP. Y AND DENUDATION. 249 

jying the chalk (the residue of its dissolution 
"by rain-water) or from the chalk itself. 

Not only do worms aid indirectly in the 
chemical disintegration of rocks, but there is 
good reason to believe that they likewise act 
in a direct and mechanical manner on the 
smaller particles. All the species which 
swallow earth are furnished with gizzards; 
and these are lined with so thick a chitinous 
membrane, that Perrier speaks of it,* as " une 
veritable armature." The gizzard is sur- 
rounded by powerful transverse muscles, 
which, according to Claparede, are about ten 
times as thick as the longitudinal ones ; and 
Perrier saw them contracting energetically. 
Worms belonging to one genus, Digaster, 
have two distinct but quite similar gizzards; 
and in another genus, Moniligaster, the 
second gizzard consists of four pouches, one 
succeeding the other, so that it may almost 
be said to have five gizzards.:]" In the same 
manner as gallinaceous and struthious birds 
swallow stones to aid in the trituration of 

* Archives de Zoolog. expeVtom. iii. 1874, p. 409. 
t ' Nouvelles Archives du Muse'um,' torn, \viii. 1872, p. 95, 
131.' 



250 DISINTEGRATION CHAP. V. 

their food, so it appears to be with terricolous 
worms. The gizzards of thirty-eight of our 
common worms were opened, and in twenty- 
five of them small stones or grains of sand, 
sometimes together with the hard calcareous 
concretions formed within the anterior cal- 
ciferous glands, were found, and in two others- 
concretions alone. In the gizzards of the 
remaining worms there were no stones; but 
some of these were not real exceptions, as 
the gizzards were opened late in the autumn, 
when the worms had ceased to feed and their 
gizzards were quite empty.* 

When worms make their burrows through 
earth abounding with little stones, no doubt 
many will be unavoidably swallowed ; but 
it must not be supposed that this fact 
accounts for the frequency with which stones 
and sand are found in their gizzards. For 
beads of glass and fragments of brick and of 
hard tiles were scattered over the surface 
of the earth, in pots in which worms were 
kept and had already made their burrows; 

* Morren, In speaking of the earth in the alimentary canals of 
worms, says, " praesepfc cum lapillis commixtam vidi : " ' De 
Lumbrici terrestris Hist. Nat.' &c., 1829, p. 16. 



CHAP. V. AND DENUDATION. 251 

and very many of these beads and fragments 
were picked up and swallowed by the worms, 
for they were found in their castings, intes- 
tines, and gizzards. They even swallowed 
the coarse red dust, formed by the pounding 
of the tiles. Nor can it be supposed that 
they mistook the beads and fragments for 
food ; for we have seen that their taste is 
delicate enough to distinguish between dif- 
ferent kinds of leaves. It is therefore 
manifest that they swallow hard objects, 
such as bits of stone, beads of glass and 
angular fragments of bricks or tiles for 
some special purpose ; and it can hardly be 
doubted that this is to aid their gizzards 
in crushing and grinding the earth, which 
they so largely consume. That such hard 
objects are not necessary for crushing 
leaves, may be inferred from the fact 
that certain species, which live in mud 
or water and feed on dead or living 
vegetable matter, but which do not swallow 
earth, are not provided with gizzards,* and 
therefore cannot have the power of utilising 
stones. 

* Perrier, 'Archives de Zoolog. exper.' torn. iii. 1874, p. 419. 



252 DISINTEGRATION CHAP. V. 

During the grinding process, the particles 
of earth must be rubbed against one another, 
and between the stones and the tough 
lining membrane of the gizzard. The softer 
particles will thus suffer some attrition, and 
will perhaps even be crushed. This con- 
clusion is supported by the appearance of 
freshly ejected castings, for these often re- 
minded me of the appearance of paint which 
has just been ground by a workman between 
two flat stones. Morren remarks that the 
intestinal canal is " impleta tenuissima terra, 
veluti in pulverem redacta." * Perrier also 
.speaks of " 1'e'tat de pate excessivement fine a 
laquelle est reduite la terre qu'ils rejettent," 



As the amount of trituration which the 
particles of earth undergo in the gizzards 
of worms possesses some interest (as we 
shall hereafter see), I endeavoured to obtain 
evidence on this head by carefully examining 
many of the fragments which had passed 
through their alimentary canals. "With 
"worms living in a state of nature, it is of 

* Morren, ' De Lumbrici terrestris Hist. Nat.' &c., p. 16. 
f ' Archives de Zoolog. expdr.' torn. iii. 1874, p. 418. 



CHAP. V. AND DENUDATION. 253 

course impossible to know how much the 
fragments may have been worn before they 
were swallowed. It is, however, clear that 
worms do not habitually select already 
rounded particles, for sharply angular bits 
of flint and of other hard rocks were often 
found in their gizzards or intestines. On 
three occasions sharp spines from the stems 
of rose-bushes were thus found. "Worms kept 
in confinement repeatedly swallowed angular 
fragments of hard tile, coal, cinders, and even 
the sharpest fragments of glass. Gallinaceous 
and struthious birds retain the same stones 
in their gizzards for a long time, which thus 
become well rounded ; but this does not 
appear to be the case with worms, judging 
from the large number of the fragments of 
tiles, glass beads, stones, &c., commonly found 
in their castings and intestines. So that 
unless the same fragments were to pass re- 
peatedly through their gizzards, visible signs 
of attrition in the fragments could hardly be 
expected, except perhaps in the case of very 
:soft stones. 

I will now give such evidence of attrition 
as I have been able to collect. In the 



254 DISINTEGKATION CHAP. Y, 

gizzards of some worms dug out of a thin bed 
of mould over the chalk, there were many well- 
rounded small fragments of chalk, and two 
fragments of the shells of a land-mollusc (as 
ascertained by their microscopical structure), 
which latter were not only rounded but 
somewhat polished. The calcareous concre- 
tions formed in the calciferous glands, which 
are often found in their gizzards, intestines, 
and occasionally in their castings, when of 
large size, sometimes appeared to have been 
rounded ; but with all calcareous bodies 
the rounded appearance may be partly or 
wholly due to their corrosion by carbonic 
acid and the humus-acids. In the gizzards 
of several worms collected in my kitchen 
garden near a hothouse, eight little frag- 
ments of cinders were found, and of these, 
six appeared more or less rounded, as were 
two bits of brick ; but some other bits were 
not at all rounded. A farm-road near 
Abinger Hall had been covered seven years 
before with brick-rubbish to the depth of 
about 6 inches ; turf had grown over this 
rubbish on both sides of the road for a 
width of 18 inches, and on this turf there 



HAP. V. AND DENUDATION. 255 

were innumerable castings. Some of them 
were coloured of a uniform red owing to 
the presence of much brick-dust, and they 
contained many particles of brick and of 
hard mortar from 1 to 3 mm. in diameter, 
most of which were plainly rounded; but 
all these particles may have been rounded 
before they were protected by the turf and 
were swallowed, like those on the bare parts 
of the road which were much worn. A hole 
in a pasture-field had been filled up with 
brick-rubbish at the same time, viz., seven 
years ago, and was now covered with turf; 
and here the castings contained very many 
particles of brick, all more or less rounded ; 
.and this brick-rubbish, after being shot into 
the hole, could not have undergone any 
attrition. Again, old bricks very little 
broken, together with fragments of mortar, 
were laid down to form walks, and were 
then covered with from 4 to 6 inches of 
gravel; six little fragments of brick were 
extracted from castings collected on these 
walks, three of which were plainly worn. 
There were also very many particles of hard 
mortar, about half of which were well 



256 DISINTEGRATION CHAP. V. 

rounded; and it is not credible that these 
could have suffered so much corrosion from 
the action of carbonic acid in the course of 
only seven years. 

Much better evidence of the attrition of 
hard objects in the gizzards of worms, is 
afforded by the state of the small fragments 
of tiles or bricks, and of concrete in the 
castings thrown up where ancient buildings 
once stood. As all the mould covering a 
field passes every few years through the 
bodies of worms, the same small fragments 
will probably be swallowed and brought to 
the surface many times in the course of cen- 
turies. It should be premised that in the 
several following cases, the finer matter was 
first washed away from the castings, and 
then all the particles of bricks, tiles and con- 
crete were collected without any selection, and 
were afterwards examined. Now in the cast- 
ings ejected between the tesserae on one of the 
buried floors of the Roman villa at Abinger, 
there were many particles (from J to 2 mm. 
in diameter) of tiles and concrete, which it 
was impossible to look at with the naked eye 
or through a strong lens, and doubt for a 



CHAP. V. AND DENUDATION. 257 

moment that they had almost all undergone 
much attrition. I speak thus after haying- 
examined small water-worn pebbles, formed 
from Roman bricks, which M. Henri de 
Saussure had the kindness to send me, and 
which he had extracted from sand and gravel 
beds, deposited on the shores of the Lake of 
Geneva, at a former period when the water 
stood at about two metres above its present 
level. The smallest of these water-worn 
pebbles of brick from Geneva resembled 
closely many of those extracted from the 
gizzards of worms, but the larger ones were 
somewhat smoother. 

Four castings found on the recently un- 
covered, tesselated floor of the great room in 
the Roman villa at Brading, contained many 
particles of tile or brick, of mortar, and of 
hard white cement ; and the majority of these 
appeared plainly worn. The particles of 
mortar, however, seemed to have suffered 
more corrosion than attrition, for grains .of 
silex often projected from their surfaces. 
Castings from within the nave of Beaulieu 
Abbey, which was destroyed by Henry VIII.,. 
were collected from a level expanse of turf,, 



258 DISINTEGBATION CHAP. V. 

overlying the buried tesselated pavement, 
through which worm-burrows passed ; and 
these castings contained innumerable particles 
of tiles and bricks, of concrete and cement, 
the majority of which had manifestly under- 
gone some or much attrition. There were 
also many minute flakes of a micaceous slate, 
the points of which were rounded. If the above 
supposition, that in all these cases the same 
minute fragments have passed several times 
through the gizzards of worms, be rejected, 
notwithstanding its inherent probability, we 
must then assume that in all the above cases 
the many rounded fragments found in the 
castings had all accidentally undergone much 
attrition before they were swallowed ; and 
this is highly improbable. 

On the other hand it must be stated that 
fragments of ornamental tiles, somewhat 
harder than common tiles or bricks, which 
had been swallowed only once by worms kept 
in confinement, were with the doubtful ex- 
ception of one or two of the smallest grains, 
not at all rounded. Nevertheless some of 
them appeared a little worn, though not 
rounded. Notwithstanding these cases, if we 



CHAP. V. AND DENUDATION. 259 

consider the evidence above given, there can 
be little 'doubt that the fragments, which serve 
as millstones in the gizzards of worms, suffer, 
when of a not very hard texture, some amount 
of attrition; and that the smaller particles in 
the earth, which is habitually swallowed in 
such astonishingly large quantities by worms, 
are ground together and are thus levigated. 
If this, be the case, the " terra tenuissima," 
the "pate excessivemerit fine," of which the 
castings largely consist, is in part due to the 
mechanical action of the gizzard ; * and this 
fine matter, as we shall see in the next chapter, 
is that which is chiefly washed away from the 
innumerable castings on every field during 
each heavy shower of rain. If the softer stones 
yield at all, the harder ones will suffer 
some slight amount of wear and tear. 

The trituration of small particles of stone 

* This conclusion reminds me of the vast amount of extremely 
fine chalky mud which is found within the lagoons of many 
atolls, where the sea is tranquil and waves cannot triturate the 
blocks of coral. This mud must, as I believe (' The Structure and 
Distribution of Coral-Reefs,' 2nd edit. 1874, p. 19), be attributed 
to the innumerable annelids and other animals which burrow 
into the dead coral, and to the fishes, Holothurians, &c., which 
browse.on the living corals. 

T 



260 DISINTEGRATION CHAP. V. 

in the gizzards of worms is of more import- 
ance under a geological point of view than 
may at fir.<t appear to be the case; for Mr. 
Sorby has clearly shown that the ordinary 
means of disintegration, namely, running 
water and the waves of the sea, act with 
less and less power on fragments of rock the 
smaller they are. " Hence," as he remarks, 
"even making no allowance for the extra 
" buoying up of very minute particles by a 
" current of water, depending on surface 
" cohesion, the effects of wearing on the form 
*' of the grains must vary directly as their 
" diameter or thereabouts. If so, a grain y 1 ^ 
" of an inch in diameter would be worn ten 
" times as much as one y^-g- of an inch in 
" diameter, and at least a hundred times as 
"much as one -y^Vff of an inch in diameter. 
** Perhaps, then, we may conclude that a 
"grain y 1 ^ of an inch in diameter would be 
" worn as much or more in drifting a mile as 
" a grain yoVg- of an inch in being drifted 
" 100 miles. On the same principle a pebble 
"one inch in diameter would be worn re- 
*' latively more by being drifted only a few 



CHAP. V. AND DENUDATION. 261 

" hundred yards." * Nor should we forget, in 
considering the power which worms exert in 
triturating particles of" rock, that there is good 
evidence that on each acre of land, which is 
sufficiently damp and not too sandy, gravelly 
or rocky for worms to inhabit, a weight of 
more than ten tons of earth annually passes 
through their bodies and is brought to the 
surface. The result for a country of the size 
of Great Britain, within a period not very 
long in a geological sense, such as a million 
years, cannot be insignificant ; for the ten tons 
of earth has to be multiplied first by the above 
number of years, and then by the number of 
acres fully stocked with worms; and in 
England, together with Scotland, the land 
which is cultivated and is well fitted for these 
animals, has been estimated at above 32 
million acres. The product is 320 million 
million tons of earth. 

* Anniversary Address : ' The Quarterly Journal of the 
Geological Soc.' May 1880, p. 59. 



T 2 



262 DENUDATION OF THE LAND CHAP. VI. 



CHAPTER VI. 

THE DENUDATION OF THE LAND Continued, 

Denudation aided by recently ejected castings flowing down 
inclined grass-covered surfaces The amount of earth which 
annually flows downwards The effect of tropical rain on 
worm castings The finest particles of earth washed com- 
pletely away from castings The disintegration of dried cast- 
ings into pellets, and their rolling down inclined surfaces 
The formation of little ledges on hill-sides, in part due to the 
accumulation of disintegrated castings Castings blown to 
leeward over level land An attempt to estimate the amount 
thus blown The degradation of ancient encampments and 
tumuli The preservation of the crowns and furrows on land 
anciently ploughed The formation and amount of mould 
over the Chalk formation. 

WE are now prepared to consider the more 
direct part which worms take in the denuda- 
tion of the land. When reflecting on sub- 
aerial denudation, it formerly appeared to 
me, as it has to others, that a nearly level or 
very gently inclined surface, covered with 
turf, could suffer no loss during even a long 
lapse of time. It may, however, be urged 
that at long intervals, debacles of rain or 



CHAP. VI, AIDED BY WORMS. 263 

water-spouts would remove all the mould 
from a i ver y gentle slope ; but when ex- 
amining the steep, turf-covered slopes in 
Glen Roy, I was struck with the fact how 
rarely any such event could have happened 
since the Glacial period, as was plain from the, 
well-preserved state of the three successive 
<4 roads" or lake-margins. But the difficulty 
in believing that earth in any .appreciable 
quantity can be removed from a gently in- 
clined surface, covered with vegetation and 
matted with roots, is removed through the. 
agency of worms. For the many castings 
which are thrown up during rain, and those 
thrown up some little time before heavy rain, 
flow for a short distance down an inclined 
surface. Moreover much of the finest levi- 
gated earth is washed completely away from 
the castings. During dry weather castings 
often disintegrate into small rounded pellets, 
and these from their weight often roll down 
any slope. This is more especially apt to 
occur when they are started by the wind, 
and probably when started by the touch of an 
animal, however small. We shall also see 
that a strong wind blows all the castings, 



264 DENUDATION OF THE LAND CHAP. VI. 

even on a level field, to leeward, whilst they 
are soft; and in like manner the pellets 
when they are dry. If the wind blows in 
nearly the direction of an inclined surface, 
the flowing down of the castings is much 
aided. 

The observations on which these several 
statements are founded must now be given in 
some detail. Castings when first ejected are 
viscid and soft ; during rain, at which time 
worms apparently prefer to eject them, they 
are still softer ; so that I have sometimes 
thought that worms must swallow much 
water at such times. However this may 
be, rain, even when not very heavy, if 
long continued, renders recently-ejected 
castings semi-fluid ; and on level ground 
they then spread out into thin, circular, flat 
discs, exactly as would so much honey or 
very soft mortar, with all traces of their 
vermiform structure lost. This latter fact 
was sometimes made evident, when a worm 
had subsequently bored through a flat circular 
disc of this kind, and heaped up a fresh 
vermiform mass in the centre. These flat 
subsided discs have been repeatedly seen b^ f 



CHAP. VI. AIDED BY WORMS. 265 

me after heavy rain, in many places on land 
of all kinds. 

On the flowing of wet castings, and tlie 
rolling of dry disintegrated castings down 
inclined surfaces. When castings are ejected 
on an inclined surface during or shortly 
before heavy rain, they cannot fail to flow a 
little down the slope. Thus, on some steep 
slopes in Knole Park, which were covered 
with coarse grass and had apparently existed 
in this state from time immemorial, I found 
(Oct. 22, 1872) after several wet days that 
almost all the many castings were con- 
siderably elongated in the line of the slope ; 
and that they now consisted of smooth, only 
slightly conical masses. Whenever the 
mouths of the burrows could be found from 
which the earth had been ejected, there was 
more earth below than above them. After 
some heavy storms of rain (Jan. 25, 1872) 
two rather steeply inclined fields near Down, 
which had formerly been ploughed and were 
now rather sparsely clothed with poor grass, 
were visited, and many castings extended 
down the slopes for a length of 5 inches, 
which was twice or thrice the usual diameter 



26ft DENUDATION OP THE LAND CHAP. Vl 

of the castings thrown up on the level parts 
of these same fields. On some fine grassy 
slopes in Holwood Park, inclined at angles 
between 8 and 11 30' with the horizon, 
where the surface apparently had never been 
disturbed by the hand of man, castings 
abounded in extraordinary numbers : and a 
space 16 inches in length transversely to the 
slope and 6 inches in the line of the slope, 
was completely coated, between the blades of 
grass, with a uniform sheet of confluent and 
subsided castings. Here also in many places 
the castings had flowed down the slope, and 
now formed smooth narrow patches of earth, 
6, 7, and 7J inches in length. Some of these 
consisted of two castings, one above the other, 
which had become so completely confluent 
that they could hardly be distinguished. On 
my lawn, clothed with very fine grass, most 
of the castings are black, but some are 
yellowish from earth having been brought 
up from a greater depth than usual, and the 
flowing-down of these yellow castings after 
heavy rain, could be clearly seen where the 
slope was 5 ; and where it was less than 1 
some evidence of their flowing down could 



CHAP. VI. AIDED BY WORMS. 267 

still be detected. On another occasion, after 
rain which was never heavy, but which lasted 
for 18 hours, all the castings on this same 
gently inclined lawn had lost their vermiform 
structure ; and they had flowed, so that fully 
two-thirds of the ejected earth lay below the 
mouths of the burrows. 

These observations led me to make others 
with more care. Eight castings were found on 
my lawn, where the grass-blades are fine and 
close together, and three others on a field with 
coarse grass. The inclination of the surface at 
the eleven places where these castings were 
collected varied between 4 30' and 17 30' ; 
the mean of the eleven inclinations being 
9 26'. The length of the castings in the 
direction of the slope was first measured with 
as much accuracy as their irregularities would 
permit. It was found possible to make these 
measurements within about ^ of an inch, but 
one of the castings was too irregular to admit 
of measurement. The average length in the 
direction of the slope of the remaining ten 
castings was 2*03 inches. The castings were 
then divided with a knife into two parts along 
a horizontal line passing through the mouth 



268 DENUDATION OF THE LAND CHAP. VI. 

of the burrow, which was discovered by slicing 
off the turf; and all the ejected earth was 
separately collected, namely, the part above 
the hole and the part below. Afterwards 
these two parts were weighed. In every 
case there was much more earth below than 
above ; the mean weight of that above being 
103 grains, and of that below 205 grains ; so 
that the latter was very nearly double the 
former. As on level ground castings are 
commonly thrown up almost equally round 
the mouths of the burrows, this difference in 
weight indicates the amount of ejected earth 
which had flowed down the slope. But very 
many more observations would be requisite 
to arrive at any general result ; for the 
nature of the vegetation and other accidental 
circumstances, such as the heaviness of the 
rain, the direction and force of the wind, &c., 
appear to be more important in determining 
the quantity of the earth which flows down a 
slope than its angle. Thus with four castings 
on my lawn (included in the above eleven) 
where the mean slope was 7 19', the difference 
in the amount of earth above and below the 
burrows was greater than with three other 



CHAP. VI. AIDED BY WORMS. 269 

castings on the- same lawn where the mean 
slope was 12 5'. 

We may, however, take the above eleven 
cases, which are accurate as far as they go, 
and calculate the weight of the ejected earth 
which annually flows down a slope having a 
mean inclination of 9 26'. This was done 
by my son George. It has been shown 
that almost exactly two-thirds of the ejected 
earth is found below the mouth of the 
burrow and one-third above it. Now if the 
two-thirds which is below the hole be divided 
into two equal parts, the upper half of this 
two-thirds exactly counterbalances the one- 
third which is above the hole, so that as far 
as regards the one-third above and the upper 
half of the two-thirds below, there is no flow 
of earth down the hill-side. The earth con- 
stituting the lower half of the two-thirds is, 
however, displaced through distances which 
are different for every part of it, but which 
may be represented by the distance between 
the middle point of the lower half of the 
two-thirds and the hole. So that the average 
distance of displacement is a half of the 
whole length of the worm-casting, Now the 



270 DENUDATION OF THE LAND CHAP. VI. 

average length of ten out of the ahove eleven 
castings was 2*03 inches, and half of this we 
may take as heing 1 inch. It may therefore 
be concluded that one-third of the whole 
earth brought to the surface was in these 
cases carried down the slope through 1 inch.* 
It was shown in the third chapter that on 
Leith Hill Common, dry earth weighing at 
least 7'453 Ibs. was brought up by worms to 
the surface on a square yard in the course of 
a year. If a square yard be drawn on a 
hill-side with two of its sides horizontal, then 
it is clear that only -^g- part of the earth 
brought up on that square yard would be 
near enough to its lower side to cross it, 
supposing the displacement of the earth to 
be through one inch. But it appears that 
only ^ of the earth brought up can be con- 
sidered to flow downwards ; hence -g- of -^ or 
y^-g- of V'453 Ibs. will cross the lower side of 
our square yard in a year. Now -j-J^ of 
7'453 Ibs. is I'l oz. Therefore I'l oz. of dry 
earth will annually cross each linear yard run- 

* Mr James Wallace Has pointed out that it is necessary to 
take into consideration the possibility of burrows being made at 
right angles to the surface instead of vertically down, in which 
case the lateral displacement of the soil would be increased. 



CHAP. VI. AIDED BY WORMS. 271 

ning horizontally along a slope having the 
above inclination ; or very nearly 7 Ibs. will 
annually cross a horizontal line, 100 yards in 
length, on a hill-side having this inclination. 

A more accurate, though still very rough, 
calculation can be made of the bulk of earth, 
which in its natural damp state annually 
flows down the same slope over a yard-line 
drawn horizontally across it. From the 
several cases given in the third chapter, it 
is known that the castings annually brought 
to the surface on a square yard, if uniformly 
spread out would form a layer *2 of an incli 
in thickness : it therefore follows by a 
calculation similar to the one already given, 
that -J- of "2 x 36, or 2'4 cubic inches of damp 
earth will annually cross a horizontal line one 
yard in length on a hill-side with the above 
inclination. This bulk of damp castings 
was found to weigh 1*85 oz. Therefore 
11*56 Ibs. of damp earth, instead of 7" Ibs. of 
dry earth as by the former calculation, would 
annually cross a line 100 yards in length on 
our inclined surface. 

In these calculations it has been assumed 
that the castings flow a short distance down- 



272 DENUDATION OF THE LAND CHAP. VI. 

wards during the whole year, but this occurs 
only with those ejected during or shortly 
before rain ; so that the above results are 
thus far exaggerated. On the other hand, 
during rain much of the finest earth is 
washed to a considerable distance from the 
castings, even where the slope is an ex- 
tremely gentle one, and is thus wholly lost 
as far as the above calculations are concerned. 
Castings ejected during dry weather and 
which have set hard, lose in the same 
manner a considerable quantity of fine earth. 
Dried castings, moreover, are apt to disinte- 
grate into little pellets, which often roll or 
are blown down any inclined surface. There- 
fore the above result, namely, that 2'4 cubic 
inches of earth (weighing T85 oz. whilst 
damp) annually crosses a yard-line of the 
specified kind, is probably not much if at all 
exaggerated. 

This amount is small ; but we should bear 
in mind how many branching valleys inter- 
sect most countries, the whole length of 
which must be very great ; and that earth is 
steadily travelling down both turf-covered 
sides of each valley. For every 100 yards in 



CHAP. VI. AIDED BY WORMS. 273 

length in a valley with sides sloping as in the 
foregoing cases, 480 cubic inches of damp 
earth, weighing above 23 pounds, will annu- 
ally reach the bottom. Here a thick bed of 
alluvium will accumulate, ready to be washed 
away in the course of centuries, as the stream 
in the middle meanders from side to side. 

If it could be shown that worms generally 
excavate their burrows at right angles to 
an inclined surface, and this would be 
their shortest course for bringing up earth 
from beneath, then as the old burrows col- 
lapsed from the weight of the superincum- 
bent soil, the collapsing would inevitably 
cause the whole bed of vegetable mould to 
sink or slide slowly down the inclined sur- 
face. But to ascertain the direction of many 
burrows was found too difficult and trouble- 
some. A straight piece of wire was, however, 
pushed into twenty-five burrows on several 
sloping fields, and in eight cases the burrows 
were nearly at right angles to the slope ; whilst 
in the remaining cases they were indifferently 
directed at various angles, either upwards or 
downwards with respect to the slope. 

In countries where the rain is very heavy, 



274 DENUDATION OF THE LAND CHAP. VI, 

as in the tropics, the castings appear, as 
might have been expected, to be washed 
down in a greater degree than in England. 
Mr. Scott informs me that near Calcutta the 
tall columnar castings (previously described), 
the diameter of which is usually between 1 
and 1^ inch, subside on a level surface, 
after heavy rain, into almost circular, thin, 
flat discs, between 3 and 4 and sometimes 5 
inches in diameter. Three fresh castings, 
which had been ejected in the Botanic 
Gardens "on a slightly inclined, grass- 
" covered, artificial bank of loamy clay," were 
carefully measured, and had a mean height 
of 2*17, and a mean diameter of T43 inches ; 
these after heavy rain, formed elongated 
patches of earth, with a mean length in the 
direction of the slope of 5*83 inches. As the 
earth had spread very little up the slope, a 
large part, judging from the original diameter 
of these castings, must hava flowed bodily 
downwards about 4 inches. Moreover some 
of the finest earth of which they were com- 
posed must have been washed completely 
away to a still greater distance. In drier 
sites near Calcutta, a species of worm ejects 



CHAP. VI. AIDED BY WORMS. 275 

its castings, not in vermiform masses, but in 
little pellets of varying sizes : these are very 
numerous in some places, and Mr. Scott says 
that they " are washed away by every 
" shower." 

I was led to believe that a considerable 
quantity of fine earth is washed quite away 
from castings during rain, from the surfaces 
of old ones being often studded with coarse 
particles. Accordingly a little fine precipi- 
tated chalk, moistened with saliva or gum- 
water, so as to be slightly viscid and of the 
same consistence as a fresh casting, was 
placed on the summits of several castings and 
gently mixed with them. These castings 
were then watered through a very fine rose, 
the drops from which were closer together 
than those of rain, but not nearly so large as 
those in a thunder-storm ; nor did they strike 
the ground with nearly so much force as 
drops during heavy rain. A casting thus 
treated subsided with surprising slowness, 
owing as I suppose to its viscidity. It did 
not flow bodily down the grass-covered sur- 
face of the lawn, which was here inclined at 
an angle of 16 20'; nevertheless many pax 1 

u 



276 DENUDATION OF THE LAND CHAP. VI. 

tides of the chalk were found three inches 
below the casting. The experiment was re- 
peated on three other castings on different 
parts of the lawn, which sloped at 2 30', 
3 and 6; and particles of chalk could be 
seen between 4 and 5 inches below the cast- 
ing ; and after the surface had become dry, 
particles were found in two cases at a distance 
of 5 and 6 inches. Several other castings 
with precipitated chalk placed on their 
summits were left to the natural action of 
the rain. In one case, after rain which was 
not heavy, the casting was longitudinally 
streaked with white. In two other cases the 
surface of the ground was rendered some- 
what white for a distance of one inch from 
the casting ; and some soil collected at a dis- 
tance of 2J- inches, where the slope was 7, 
effervesced slightly when placed in acid. 
After one or two weeks, the chalk was wholly 
or almost wholly washed away from all the 
castings on which it had been placed, and 
these had recovered their natural colour. 

It may be here remarked that after very 
heavy rain shallow pools may be seen on level 
or nearly level fields, where the soil is not 



CHAP. VI. AIDED BY WORMS 277 

very porous, and the water in them is often 
slightly muddy ; when such little pools have 
dried, the leaves and blades of grass at their 
bottoms are generally coated with a thin layer 
of mud. This mud I believe is derived in 
large part from recently ejected castings. 

Dr. King informs me that the majority of 
the before described gigantic castings, which 
he found on a fully exposed, bare, gravelly 
knoll on the Nilgiri Mountains in India, had 
been more or less weathered by the previous 
north-east monsoon ; and most of them pre- 
sented a subsided appearance. The worms 
here eject their castings only during the rainy 
season ; and at the time of Dr. King's visit no 
rain had fallen for 110 days. He carefully 
examined the ground between the place 
where these huge castings lay, and a little 
water-course at the base of the knoll, and 
nowhere was there any accumulation of fine 
earth, such as would necessarily have been 
left by the disintegration of the castings if 
they had not been wholly removed. He 
therefore has no hesitation in asserting that 
the whole of these huge castings are annually 
washed during the two monsoons (when 

u 2 



278 DENUDATION OF THE LAND CHAP. VI. 

about 100 inches of rain fall) into the little 
water-course, and thence into the plains 
lying below at a depth of 3000 or 4000 feet. 

Castings ejected before or during dry 
weather become hard, sometimes surprisingly 
hard, from the particles of earth having been 
cemented together by the intestinal secre- 
tions. Frost seems to be less effective in 
their disintegration than might have been 
expected. Nevertheless they readily disin- 
tegrate into small pellets, after being alter- 
nately moistened with rain and again dried. 
Those which have flowed during rain down a 
slope, disintegrate in the same manner. Such 
pellets often roll a little down any sloping 
surface ; their descent being sometimes much 
aided by the wind. The whole bottom of a 
broad dry ditch in my grounds, where there 
were very few fresh castings, was completely 
covered with these pellets or disintegrated 
castings, which had rolled down the steep 
sides, inclined at an angle of 27. 

Near Nice, in places where the great cylin- 
drical castings, previously described, abound, 
the soil consists of very fine arenaceo-cal- 
careous loam ; and Dr. King informs me that 



CHAP. VI. AIDED BY WORMS. 279 

these castings are extremely liable to crumble 
during dry weather into small fragments, 
which are soon acted on by rain, and then 
sink down so as to be no longer distinguish- 
able from the surrounding soil. He sent me 
a mass of such disintegrated castings, collected 
on the top of a bank, where none could have 
rolled down from above. They must have 
been ejected within the previous five or six 
months, but they now consisted of more or less 
rounded fragments of all sizes, from f of an 
inch in diameter to minute grains and mere 
dust. Dr. King witnessed the crumbling 
process whilst drying some perfect castings, 
which he afterwards sent me. Mr. Scott also 
remarks on the crumbling of the castings 
near Calcutta and on the mountains of 
Sikkim during the hot and dry season. 

When the castings near Nice had been 
ejected on an inclined surface, the disinte- 
grated fragments rolled downwards, without 
losing their distinctive shape ; and in some 
places could " be collected in basketfuls." Dr. 
King observed a striking instance of this fact 
on the Corniche road, where a drain, about 
2^ feet wide and 9 inches deep, had been made 



280 DENUDATION TO LAND CHAP. VI. 

to Catch the surface drainage from the adjoin- 
ing hill-side. The bottom, of this drain was 
covered for a distance of several hundred 
yards, to a depth of from 1 J to 3 inches, by a 
layer of broken castings, still retaining their 
characteristic shape. Nearly all these in- 
numerable fragments had rolled down from 
above, for extremely few castings had been 
ejected in the drain itself. The hill-side was 
steep, but varied much in inclination, which 
Dr. King estimated at from 30 to 60 with 
the horizon. He climbed up the slope, and 
" found every here and there little embank- 
" ments, formed by fragments of the castings 
" that had been arrested in their downward 
" progress by irregularities of the surface, 
" by stones, twigs, &c. One little group of 
" plants of Anemone hortensis had acted in this 
" manner, and quite a small bank of soil had 
"collected round it. Much of this soil had 
" crumbled down, but a great deal of it still 
" retained the form of castings." Dr. King 
dug up this plant, and was struck with 
the thickness of the soil which must have 
recently accumulated over the crown of the 
rhizoma, as shown by the length of the 



CHAP. VI. LEDGES ON HILL-SIDES. 281 

bleached petioles, in comparison with those 
of other plants of the same kind, where 
there had been no such accumulation. The 
earth thus accumulated had no doubt been 
secured (as I have everywhere seen) by the 
smaller roots of the plants. After describing 
this and other analogous cases, Dr. King con- 
cludes : " I can have no doubt that worms 
" help greatly in the process of denudation." 

Ledges of earth on steep hill-sides. Little 
horizontal ledges, one above another, have been 
observed on steep grassy slopes in many parts 
of the world. Their formation has been 
attributed to animals travelling repeatedly 
along the slope in the same horizontal lines 
while grazing, and that they do thus move and 
use the ledges is certain ; but Professor Hens- 
low (a most careful observer) told Sir J. Hooker 
that he was convinced that this was not the 
sole cause of their formation. Sir J. Hooker 
saw such ledges on the Himalayan and Atlas 
ranges, where there were no domesticated 
animals and not many wild ones ; but these 
latter would, it is probable, use the ledges at 
night while grazing like our domesticated 
animals. A friend observed for me the ledges 



282 DENUDATION TO LAND CHAP. VI 

on the Alps of Switzerland, and states that 
they ran at 3 or 4 ft. one above the other, 
and were about a foot in breadth. They had 
been deeply pitted by the feet of grazing cows. 
Similar ledges were observed by the same 
friend on our Chalk downs, and on an old 
talus of chalk-fragments (thrown out of a 
quarry) which had become clothed with turf. 
My son Francis examined a Chalk escarp- 
ment near Lewes ; and here on a part which 
was very steep, sloping at 40 with the 
horizon, about 30 flat ledges extended hori- 
zontally for more than 100 yards, at an average 
distance of about 20 inches, one beneath the 
other. They were from 9 to 10 inches in 
breadth. When viewed from a distance they 
presented a striking appearance, owing to their 
parallelism ; but when examined closely, they 
were seen to be somewhat sinuous, and one 
often ran into another, giving the appearance 
of the lodge having forked into two. They 
are formed of light-coloured earth, which on 
the outside, where thickest, was in one case 
9 inches, and in another case between 6 and 
7 inches in thickness. Above the ledges, the 
thickness of the earth over the chalk was in 



HAP. VI. LEDGES ON HILL-SIDES. 283 

the former case 4 and in the latter only 3 
inches. The grass grew more vigorously on 
the outer edges of the ledges than on any 
other part of the slope, and here formed a 
tufted fringe. Their middle part was bare, but 
whether this had been caused by the trampling 
of sheep, which sometimes frequent the ledges, 
my son could not ascertain. Nor could he 
feel sure how much of the earth on the middle 
and bare parts, consisted of disintegrated 
worm-castings which had rolled down from 
above ; but he felt convinced that some had 
thus originated ; and it was manifest that the 
ledges with their grass-fringed edges would 
arrest any small object rolling down from 
above. 

At one end or side of the bank bearing 
these ledges, the surface consisted in parts of 
bare chalk, and here the ledges were very 
irregular. At the other end of the bank, the 
slope suddenly became less steep, and here the 
ledges ceased rather abruptly ; but little em- 
bankments only a foot or two in length were 
still present. The slope became steeper lower 
down the hill, and the regular ledges then re- 
appeared. Another of my sons observed, on 



284 DENUDATION TO LAND CHAP. VL 

the inland side of Beacliy Head, where the 
surface sloped at about 25, many short little 
embankments like those just mentioned. 
They extended horizontally and were from a 
few inches to two or three feet in length. 
They supported tufts of grass growing 
vigorously. The average thickness of the 
mould of which they were formed, taken 
from nine measurements, was 4*5 inches; 
while that of the mould above and beneath 
them was on an average only 3*2 inches, and 
on each side, on the same level, 3*1 inches. 
On the upper parts of the slope, these em- 
bankments showed no signs of having been 
trampled on by sheep, but in the lower parts 
such signs were fairly plain. No long con- 
tinuous ledges had here been formed. 

If the little embankments above the Cor- 
niche road, which Dr. King saw in the act 
of formation by the accumulation of dis- 
integrated and rolled worm-castings, were to 
become confluent along horizontal lines, ledges 
would be formed. Each embankment would 
tend to extend laterally by the lateral extension 
of the arrested castings; and animals grazing on 
a steep slope would almost certainly make use 



CHAP. VI. LEDGES ON HILL-SIDES. 285 

of every prominence at nearly the same level, 
and would indent the turf between them ; and 
such intermediate indentations would again 
arrest the castings. An irregular ledge when 
once formed would also tend to become more 
regular and horizontal by some of the castings 
rolling laterally from the higher to the lower 
parts, which would thus be raised. Any pro- 
jection beneath a ledge would not afterwards 
receive disintegrated matter from above, 
and would tend to be obliterated by rain and 
other atmospheric agencies. There is some 
analogy between the formation, as here sup- 
posed, of these ledges, and that of the ripples 
of wind-drifted sand as described by Lyell.* 

The steep, grass-covered sides of a 
mountainous valley in Westmoreland, called 
Grisedale, was marked in many places with 
innumerable lines of miniature cliffs, with 
almost horizontal, little ledges at their bases. 
Their formation was in no way connected with 
the action of worms, for castings could not 
anywhere be seen (and their absence is an 
inexplicable fact), although the turf lay in 
many places over a considerable thickness of 

* 'Elements of Geology,' 1865, p. 20. 



286 DENUDATION OF THE LAND. CHAP. VI. 

boulder-clay and moraine rubbish. Nor, as 
far as I could judge, was the formation of 
these little cliffs at all closely connected with 
the trampling of cows or sheep. It appeared 
as if the whole superficial, somewhat argil- 
laceous earth, while partially held together 
by the roots of the grasses, had slided a little 
way down the mountain sides; and in thus 
sliding, had yielded and cracked in horizontal 
lines, transversely to the slope. 

Castings blown to leeward by the wind. We 
have seen that moist castings flow, and that 
disintegrated castings roll down any inclined 
surface ; and we shall now see that castings, 
recently ejected on level grass-covered 
surfaces, are blown during gales of wind ac- 
companied by rain to leeward. This has been 
observed by me many times on many fields 
during several successive years. After such 
gales, the castings present a gently inclined 
and smooth, or sometimes furrowed, surface 
to windward, while they are steeply inclined 
or precipitous to leeward, so that they resem- 
ble on a miniature scale glacier-ground hillocks 
of rock. They are often cavernous on the 



CHAP. VI. CASTINGS BLOWN TO LEEWAKD. 287 

leeward side, from the upper part having 
curled over the lower part During one un- 
usually heavy south-west gale with torrents 
of rain, many castings were wholly blown to 
leeward, so that the mouths of the burrows 
were left naked and exposed on the windward 
side. Eecent castings naturally flow down 
an inclined surface, but on a grassy field, 
which sloped between 10 and 15, several 
were found after a heavy gale blown up the 
slope. This likewise occurred on another 
occasion on a part of my lawn where the 
slope was somewhat less. On a third occasion, 
the castings on the steep, grass-covered sides 
of a valley, down which a gale had blown, 
were directed obliquely instead of straight 
down the slope ; and this was obviously due 
to the combined action of the wind and 
gravity. Four castings on my lawn, where 
the downward inclination was 45', 1, 3 and 
3 30' (mean 2 45') towards the north-east, 
after a heavy south-west gale with rain, were 
divided across the mouths of the burrows and 
weighed in the manner formerly described. 
The mean weight* of the earth below the 
mouths of burrows and to leeward, was to that 



288 DENUDATION OF THE LAND. CHAP. VI. 

above the mouths and on the windward side 
as 2 1 to 1 ; whereas we have seen that with 
several castings which had flowed down slopes 
having a mean inclination of 9 26', and with 
three castings where the inclination was 
above 12, the proportional weight of the 
earth below to that above the burrows was 
as only 2 to 1. These several cases show how 
efficiently gales of wind accompanied by rain 
act in displacing recently-ejected castings. 
"We may therefore conclude that even a 
moderately strong wind will produce some 
slight effect on them 

Dry and indurated castings, after their dis- 
integration into small fragments or pellets, are 
sometimes, probably often, blown by a strong 
wind to leeward. This was observed on four 
occasions, but I did not sufficiently attend to 
this point. One old casting on a gently slop- 
ing bank was blown quite away by a strong 
south-west wind. Dr. King believes that 
the wind removes the greater part of the 
old crumbling castings near Nice. Several 
old castings on my lawn were marked with 
pins and protected from any disturbance. 
They were examined after an interval of 10 



CHAP. VI. CASTINGS BLOWN TO LEEWAED. 289 

weeks, during which time the weather had 
been alternately dry and rainy. Some, which 
were of a yellowish colour had been washed 
almost completely away, as could be seen 
by the colour of the surrounding ground. 
Others had completely disappeared, and these 
no doubt had been blown away. Lastly, 
others still remained and would long remain, 
as blades of grass had grown through them. 
On poor pasture land, which has never been 
rolled and has not been much trampled on 
by animals, the whole surface is sometimes 
dotted with little pimples, through and on 
which grass grows; and these pimples con- 
sist of old worm-castings. 

In all the many observed cases of soft cast 
ings blown to leeward, this had been effected 
by strong winds accompanied by rain. As 
such winds in England generally blow from 
the south and south-west, earth must on the 
whole tend to travel over our fields in a 
north and north-east direction. This fact is 
interesting, because it might be thought that 
none could be removed from a level, grass- 
covered surface by any means. In thick and 
level woods, protected from the wind, castings 



290 DENUDATION OF THE LAND. CHAP. VI 

will never be removed as long as the wood 
lasts ; and mould will here tend to accumulate 
to the depth at which worms can work. I 
tried to procure evidence as to how much 
mould is blown, whilst in the state of cast- 
ings, by our wet southern gales to the north- 
east, over open and flat land, by looking to 
the level of the surface on opposite sides of 
old trees and hedge-rows ; but I failed owing 
to the unequal growth of the roots of trees 
and to most pasture-land having been formerly 
ploughed. 

On an open plain near Stonehenge, there 
exist shallow circular trenches, with a low 
embankment outside, surrounding level spaces 
50 yards in diameter. These rings appear 
very ancient, and are believed to be contem- 
poraneous with the Druidical stones. Castings 
ejected within these circular spaces, if blown 
to the north-east by south-west winds would 
form a layer of mould within the trench, 
thicker on the north-eastern than on any other 
side. But the site was not favourable for the 
action of worms, for the mould over the 
surrounding Chalk formation with flints, was 
only 3-37 inches in thickness, from a mean of 



CHAP. VI. CASTINGS BLOWN TO LEEWARD. 291 

six observations made at a distance of 10 yards 
outside the embankment. The thickness of 
the mould within two of the circular trenches 
was measured every 5 yards all round, on the 
inner sides near the bottom. My son Horace- 
protracted these measurements on paper ; and 
though the curved line representing the thick- 
ness of the mould was extremely irregular, yet 
in both diagrams it could be seen to be thicker 
on the north-eastern side than elsewhere. 
When a mean of all the measurements in both- 
the trenches was laid down and the line- 
smoothed, it was obvious that the mould was 
thickest in the quarter of the circle between- 
north-west and north-east; and thinnest in> 
the quarter between south-east and south- 
west, especially at this latter point. Besides 
the foregoing measurements, six others were- 
taken near together in one of the circular 
trenches, on the north-east side; and the- 
mould here had a mean thickness of 2*29' 
inches ; while the mean of six other measure- 
ments on the south-west side was only 1'46- 
inches. These observations indicate that the 
castings had been blown by the south-west 
winds from the circular enclosed space into 

x 



292 DENUDATION OF THE LAND. CHAP. VI. 

the trench on the north-east side ; but many 
more measurements in other analogous cases 
would be requisite for a trustworthy result. 

The amount of fine earth brought to the 
surface under the form of castings, and after- 
wards transported by the winds accompanied 
by rain, or that which flows and rolls down 
an inclined surface, no doubt is small in the 
course of a few scores of years ; for otherwise 
all the inequalities in our pasture fields would 
be smoothed within a much shorter period 
than appears to be the case. But the amount 
which is thus transported in the course of 
thousands of years cannot fail to be consider- 
able and deserves attention. E. de Beaumont 
looks at the vegetable mould which every- 
where covers the land as a fixed line, 
from which the amount of denudation may 
be measured.* He ignores the continued 
formation of fresh mould by the disintegra- 
tion of the underlying rocks and fragments of 
rock ; and it is curious to find how much 
more philosophical were the views, main- 

* 'Le9ons de Geologic pratique, 1845; cinquieme Lecon.' 
All Elie de Beaumont's arguments are admirably controverted 
by Prof. A. Geikie in his essay in Transact. Geolog. Soc. of 
Glasgow, vol. iii. p. 153, 1868. 



'CHAP. VI. ANCIENT MOUNDS. 293 

tained long ago, by Play fair, who, In 1802, 
wrote, "In the permanence of a coat of 
" vegetable mould on the surface of the earth, 
" we have a demonstrative proof of the con- 
"*' tinued destruction of the rocks."* 

Ancient encampments and tumuli. E. de 
Beaumont adduces the present state of many 
ancient encampments and tumuli and of old 
ploughed fields, as evidence that the surface 
of the land undergoes hardly any degradation. 
But it does not appear that he ever examined 
~fche thickness of the mould over different 
parts of such old remains. He relies chiefly 
on indirect, but apparently trustworthy, evi- 
dence that the slopes of the old embankments 
are the same as they originally were ; and it 
is obvious that he could know nothing about 
their original heights. In Knole Park a 
mound had been thrown up behind the rifle- 
targets, which appeared to have been formed 
of earth originally supported by square blocks 
of turf. The sides sloped, as nearly as I could 
estimate them, at an angle of 45 or 50 with 
the horizon, and they were covered, especially 
on the northern side, with long coarse grass, 

* * Illustrations of the Huttonian Theory of the Earth,' p. 107. 

x 2 



294 DENUDATION OF THE LAND. CHAP. VL 

beneath which many worm-castings were 
found. These had flowed bodily downwards, 
and others had rolled down as pellets. Hence 
it is certain that as long as a mound of this 
kind is tenanted by worms, its height will be 
continually lowered. The fine earth which 
flows or rolls down the sides of such a mound 
accumulates at its base in the form of a talus. 
A bed, even a very thin bed, of fine earth is 
eminently favourable for worms ; so that a 
greater number of castings would tend to be 
ejected on a talus thus formed than elsewhere ; 
and these would be partially washed away by 
every heavy shower and be spread over the 
adjoining level ground. The final result 
would be the lowering of the whole mound,, 
whilst the inclination of the sides would not 
be greatly lessened. The same result would 
assuredly follow with ancient embankments 
and tumuli ; except where they had been 
formed of gravel or of nearly pure sand, as such 
matter is unfavourable for worms. Many old 
fortifications and tumuli are believed to be at 
least 2000 years old ; and we should bear in 
mind that in many places about one inch of 
mould is brought to the surface in 5 years or 



CHAP. VI. ANCIENTLY PLOUGHED FIELDS. 295 

two inches in 10 years. Therefore in so long 
a period as 2000 years, a large amount of 
earth will have heen repeatedly brought to 
the surface on most old embankments and 
tumuli, especially on the talus round their 
bases, and much of this earth will have been 
washed completely away. We may therefore 
conclude that all ancient mounds, when not 
formed of materials unfavourable to worms, 
will have been somewhat lowered in the 
course of centuries, although their inclina- 
tions may not have been greatly changed. 

Fields formerly ploughed. From a very 
remote period and in many countries, land 
has been ploughed, so that convex beds, 
called crowns or ridges, usually about 8 feet 
across and separated by furrows, have been 
thrown up. The furrows are directed so as 
to carry off the surface water. In my 
attempts to ascertain how long a time these 
crowns and furrows last, when ploughed land 
has been converted into pasture, obstacles of 
many kinds were encountered. It is rarely 
kuown when a field was last ploughed ; and 
some fields which were thought to have been 
in pasture from time immemorial were after- 



296* DENUDATION OF THE LAND. CHAP. VI.. 

wards discovered to- have- been ploughed only 
50 or 60 years before. During the early 
part of the present century, when the price 
of corn was very high, land of all kinds seems 
to have been ploughed in Britain. There is, 
however, no reason to doubt that in many 
cases the old crowns and furrows have been 
preserved from a very ancient period.* That 
they should have been preserved for very 
unequal lengths of time would naturally 
follow from the crowns, when first thrown 
up, having differed much in height in dif- 
ferent districts, as is now the case with 
recently ploughed land. 

In old pasture fields, the mould, wherever 
measurements were made, was found to be 
from i to 2 inches thicker in the furrows than 

* Mr. E. Tylor in his Presidential address ('Journal of the 
Anthropological Institute,' May 1880, p. 451) remarks: "It 
appears from several papers of the Berlin Society as to the 
German 'high-fields' or 'heathen-fields' (Hochacker, and 
Heidenacker) that they correspond much in their situation on hills 
and wastes with the * elf-furrows ' of Scotland, which popular 
mythology accounts for by the story of the fields having been 
put under a Papal interdict, so that people took to cultivating 
the hills.- There seems reason to suppose that, like the tilled 
plots in the Swedish forests which tradition ascribes to the old 
* hackers,' the German- heathen-fields represent tillage by an. 
ancient and barbaric population." 



CHAP. VI. ANCIENTLY PLOUGHED FIELDS. 297 

on the crowns ; but this would naturally 
follow from the finer earth having been 
washed from the crowns into the furrows 
before the land was well clothed with turf; 
and it is impossible to tell what part worms 
may have played in the work. Nevertheless 
from what we have seen, castings would 
certainly tend to flow and to be washed during 
heavy rain from the crowns into the furrows. 
But as soon as a bed of fine earth had by any 
means been accumulated in the furrows, it 
would be more favourable for worms than the 
other parts, and a greater number of castings 
would be thrown up here than elsewhere ; and 
as the furrows on sloping land are usually 
directed so as to carry off the surface water, 
some of the finest earth would be washed 
from the castings which had been here ejected 
and be carried completely away. The result 
would be that the furrows would be filled 
up very slowly, while the crowns would be 
lowered perhaps still more slowly by the 
flowing and rolling of the castings down 
their gentle inclinations into the furrows. 

Nevertheless it might be expected that old 
furrows, especially those on a sloping surface, 



-298 DENUDATION OF THE LAND. CHAP. VI. 

would in the course of time be filled up and 
disappear. Some careful observers, however, 
who examined fields for me in Gloucestershire 
and Staffordshire, could not detect any dif- 
ference in the state of the furrows in the 
upper and lower parts of sloping fields, sup- 
posed to have been long in pasture ; and they 
came to the conclusion that the crowns and 
furrows would last for an almost endless 
number of centuries. On the other hand the 
process of obliteration seems to have com- 
menced in some places. Thus in a grass 
field in North Wales, known to have been 
ploughed about 65 years ago, which sloped at 
an angle of 15 to the north-east, the depth 
of the furrows (only 7 feet apart) was care- 
fully measured, and was found to be about 
4 J inches in the upper part of the slope, and 
only 1 inch near the base, where they could 
be traced with difficulty. On another field 
sloping at about the same angle to the south- 
west, the furrows were scarcely perceptible 
in the lower part ; although these same 
furrows when followed on to some adjoining 
level ground were from 2^ to 3J inches in 
depth. A third and closely similar case was 



OHAP. VI. ANCIENTLY PLOUGHED FIELDS. 299 

observed. In a fourth case, the mould in a 
furrow in the upper part of a sloping field 
was 2J inches, and in the lower part 4^ 
inches in thickness. 

On the Chalk Downs at about a mile dis- 
tance from Stonehenge, my son William ex- 
amined a grass-covered, furrowed surface, 
sloping at from 8 to 10, which an old shep- 
herd said had not been ploughed within the 
memory of man. The depth of one furrow 
was measured at 16 points in a length of 68 
paces, and was found to be deeper where the 
slope was greatest and where less earth would 
naturally tend to accumulate, and at the 
base it almost disappeared. The thickness of 
the mould in this furrow in the upper part 
was 2t| inches, which increased to 5 inches a 
little above the steepest part of the slope ; and 
at the base, in the middle of the narrow 
valley, at a point which the furrow if con- 
iinued would have struck, it amounted to 7 
inches. On the opposite side of the valley, 
there were very faint, almost obliterated, 
traces of furrows. Another analogous but 
not so decided a case was observed at a few 
miles' distance from Stonehenge. On the 



300 DENUDATION OF THE LAND. CHAP. VI. 

whole it appears that the crowns and fur- 
rows on land formerly ploughed, but now 
covered with grass, tend slowly to disappear 
when the surface is inclined ; and this is pro- 
bably in large part due to the action of 
worms ; but that the crowns and furrows last 
for a very long time when the surface is 
nearly level. 

Formation and amount of mould over the 
Chalk Formation. Worm-castings are often 
ejected in extraordinary numbers on steep, 
grass-covered slopes, where the Chalk comes 
close to the surface, as my son William 
observed near Winchester and elsewhere. If 
such castings are largely washed away during 
heavy rains, it is difficult to understand at 
first how any mould can still remain on our 
Downs, as there does not appear any evident 
means for supplying the loss. There is, more- 
over, another cause of loss, namely, in the per- 
colation of the finer particles of earth into the 
fissures in the chalk and into the chalk itself. 
These considerations led me to doubt for a time 
whether I had not exaggerated the amount 
of fine earth which flows or rolls down grass- 
covered slopes under the form of castings ; and 



CHAP. VI. MOULD OVER THE CHALK. SOX 

I sought for additional information. In some 
places, the castings on Chalk Downs consist 
largely of calcareous matter, and here the 
supply is of course unlimited. But in other- 
places, for instance on a part of Teg Down 
near Winchester, the castings were all black 
and did not effervesce with acids. The mould 
over the chalk was here only from 3 to 4 
inches in thickness. So again on the plain 
near Stonehenge, the mould, apparently free 
from calcareous matter, averaged rather less 
than 3J inches in thickness. Why worms 
should penetrate and bring up chalk in some 
places and not in others I do not know. 

In many districts where the land is nearly 
level, a bed several feet in thickness of red 
clay full of unworn flints overlies the Upper 
Chalk. This overlying matter, the surface 
of which has been converted into mould, con- 
sists of the undissolved residue from the chalk. 
It may be well here to recall the case of the 
fragments of chalk buried beneath worm- 
castings on one of my fields, the angles of 
which were so completely rounded in the 
course of 29 years that the fragments now 
resembled water-worn pebbles. This must 



302 DENUDATION OF THE LAND. CHAP. VL 

have been effected by the carbonic acid in 
the rain and in the ground, by the humus- 
acids, and by the corroding power of living 
roots. Why a thick mass of residue has not 
been left on the Chalk, wherever the land is 
nearly level, may perhaps be accounted for 
by the percolation of the fine particles into 
the fissures, which are often present in the 
chalk and are either open or are filled up 
with impure chalk, or into the solid chalk 
itself. That such percolation occurs can 
hardly be doubted. My son collected some 
powdered and fragmentary chalk beneath the 
turf near Winchester ; the former was found 
by Colonel Parsons, R.E., to contain 10 per 
cent., and the fragments 8 per cent, of earthy 
matter. On the flanks of the escarpment near 
Abinger in Surrey, some chalk close beneath 
a layer of flints, 2 inches in thickness and 
covered by 8 inches of mould, yielded a re- 
sidue of 3'7 per cent, of earthy matter. On 
the other hand the Upper Chalk properly 
contains, as I was informed by the late David 
Forbes who had made many analyses, only 
from 1 to 2 per cent, of earthy matter ; and 
two samples from pits near my house con- 



CHAP. VI. MOULD OVER THE CHALK. SOS 

tained 1*3 and 0'6 per cent. I mention these 
latter cases because, from the thickness of the 
overlying bed of red clay with flints, I had 
imagined that the underlying chalk might 
here be less pure than elsewhere. The cause 
of the residue accumulating more in some 
places than in others, may be attributed to a 
layer of argillaceous matter having been left 
at an early period on the chalk, and this 
would check the subsequent percolation of 
earthy matter into it. 

From the facts now given we may conclude 
that castings ejected on our Chalk Downs suffer 
some loss by the percolation of their finer 
matter into the chalk. But such impure 
superficial chalk, when dissolved, would leave 
a larger supply of earthy matter to be 
added to the mould than in the case of pure 
chalk. Besides the loss caused by percola- 
tion, some fine earth is certainly washed 
down the sloping grass-covered surfaces of 
our Downs. The washing-down process, how- 
ever, will be checked in the course of time ; 
for although I do not know how thin a layer 
of mould suffices to support worms, yet a limit 
must at last be reached ; and then their cast- 



304 DENUDATION OF THE LAND. CHAP. VI. 

ings would cease to be ejected or would 
become scanty. 

The following cases show that a consider- 
able quantity of fine earth is washed down. 
The thickness of the mould was measured at 
points 12 yards apart across a small valley 
in the Chalk near Winchester. The sides 
sloped gently at first ; then became inclined 
at about 20 ; then more gently to near the 
bottom, which transversely was almost level 
and about 50 yards across. In the bottom, 
the mean thickness of the mould from five 
measurements was 8'3 inches; whilst on the 
sides of the valley, where the inclination 
varied between 14 and 20, its mean thick- 
ness was rather less than 3*5 inches. As the 
turf-covered bottom of the valley sloped at an 
angle of only between 2 and 3, it is probable 
that most of the 8'3-inch layer of mould had 
been was'hed down from the flanks of the 
valley, and not from the upper part. But as 
a shepherd said that he had seen water flow- 
ing in this valley after the sudden thawing of 
snow, it is possible that some earth may have 
been brought down from the upper part ; or, 
on the other hand, that some may have been 



CHAP. VI. MOULD OVER THE CHALK. 305 

carried further down the valley. Closely 
similar results, with respect to the thickness of 
the mould, were obtained in a neighbouring 
valley. 

St. Catherine's Hill, near Winchester, is 
327 feet in height, and consists of a steep 
cone of chalk about 1 of a mile in diameter. 
The upper part was converted by the Romans, 
or, as some think, by the ancient Britons, into 
an encampment, by the excavation of a deep 
and broad ditch all round it. Most of the 
chalk removed during the work was thrown 
upwards, by which a projecting bank was 
formed ; and this effectually prevents worm- 
castings (which are numerous in parts), stones, 
and other objects from being washed or rolled 
into the ditch. The mould on the upper and 
fortified part of the hill was found to be in 
most places only from 2J to 3^ inches in 
thickness ; whereas it had accumulated at the 
foot of the embankment above the ditch to a 
thickness in most places of from 8 to 9J 
inches. On the embankment itself the mould 
was only 1 to 1J inch in thickness; and 
within the ditch at the bottom it varied from 
2% to 3J, but was in one spot 6 inches in 



306 DENUDATION OP THE LAND. CHAP. VL 

thickness. On the north-west side of the 
hill, either no embankment had ever heen 
thrown up above the ditch, or it had subse- 
quently been removed ; so that here there 
was nothing to prevent worm-castings, earth 
and stones being washed into the ditch, at the 
bottom of which the mould formed a layer 
from 11 to 22 inches in thickness. It should 
however be stated that here and on other 
parts of the slope, the bed of mould often con- 
tained fragments of chalk and flint which 
had obviously rolled down at different times 
from above. The interstices in the under- 
lying fragmentary chalk were also filled up 
with mould. 

My son examined the surface of this hill to 
its base in a south-west direction. Beneath 
the great ditch, where the slope was about 
24, the mould was very thin, namely, from 
l to 2 inches ; whilst near the base, where 
the slope was only 3 to 4, it increased to 
between 8 and 9 inches in thickness. We 
may therefore conclude that on this artificially 
modified hill, as well as in the natural valleys 
of the neighbouring Chalk Downs, some fine 
earth, probably derived in large part from 



CHAP. VI. MOULD OVER THE CHALK. 307 

worm-castings, is washed down, and accumu- 
lates in the lower parts, notwithstanding the 
percolation of an unknown quantity into the 
underlying chalk ; a supply of fresh earthy 
matter being afforded by the dissolution of 
the chalk through atmospheric and other 
agencies. 



30& CONCLUSION. CHAP. VIL 



CHAPTER VII. 

CONCLUSION. 

Summary of the part which worms have played in the history 
of the world Their aid in the disintegration of rocks In the 
denudation of the land In the preservation of ancient remains- 
In the preparation of the soil for the growth of plants 
Mental powers of worms Conclusion. 

WORMS have played a more important part 
in the history of the world than most persons 
would at first suppose. In almost all humid 
countries they are extraordinarily numerous, 
and for their size possess great muscular 
power. In many parts of England a weight 
of more than ten tons (10,516 kilogrammes) 
of dry earth annually passes through their 
bodies and is brought to the surface on each 
acre of land ; so that the whole superficial 
bed of vegetable mould passes through their 
bodies in the course of every few years 
From the collapsing of the old burrows the 
mould is in constant though slow movement, 



CHAP. VII. CONCLUSION. 309 

and the particles composing it are thus 
rubbed together. By these means fresh sur- 
faces are continually exposed to the action of 
the carbonic acid in the soil, and of the 
humus-acids which appear to be still more 
efficient in the decomposition of rocks. The 
generation of the humus-acids is probably 
hastened during the digestion of the many 
half-decayed leaves which worms consume. 
Thus the particles of earth, forming the 
superficial mould, are subjected to conditions 
eminently favourable for their decomposition 
and disintegration. Moreover, the particles 
of the softer rocks suffer some amount of 
mechanical trituration in the muscular giz- 
zards of worms, in which smail stones serve 
as mill-stones. 

The finely levigated castings, when brought 
to the surface in a moist condition, flow during 
rainy weather down any moderate slope ; and 
the smaller particles are washed far down 
even a gently inclined surface. Castings 
when dry often crumble into small pellets 
and these are apt to roll down any sloping 
surface. Where the land is quite level and 
is covered with herbage, and where the 

T 2 



CONCLUSION. CHAP. VIL 

climate is humid so that much dust cannot be 
blown away, it appears at first sight im- 
possible that there should be any appreciable 
amount of sub-aerial denudation ; but worm- 
'Castings are blown, especially whilst moist 
and viscid, in one uniform direction by the 
prevalent winds which are accompanied by 
rain. By these several means the superficial 
mould is prevented from accumulating to a 
great thickness ; and a thick bed of mould 
checks in many ways the disintegration of 
,the underlying rocks and fragments of rock. 

The removal of worm-castings by the above 
i means leads to results which are far from 
insignificant. It has been shown that a 
layer of earth, *2 of an inch in thickness, is in 
many places annually brought to the surface ; 
.and if a small part of this amount flows, or 
rolls, or is washed, even for a short distance, 
down every inclined surface, or is repeatedly 
blown in one direction, a great effect will 
Jbe produced in the course of ages. It was 
found by measurements and calculations that 
on a surface with a mean inclination of 
9 26', 2'4 cubic inches of earth which had 
been ejected by worms crossed, in the course 



CHAP. VII. CONCLUSION. 31$ 

of a year, a horizontal line one yard in length; 
so that 240 cubic inches would cross a line 
100 yards in length. This latter amount in a 
damp state would weigh 114 pounds. Thus- 
a considerable weight of earth is continually 
moving down each side of every valley, and 
will in time reach its bed. Finally this earth 
will be transported by the streams flowing in 
the valleys into the ocean, the great receptacle- 
for all matter denuded from the land. It is- 
known from the amount of sediment annually 
delivered into the sea by the Mississippi, that 
its enormous drainage-area must on an aver- 
age be lowered "00263 of an inch each year - 
and this would suffice in four and half million 
years to lower the whole drainage-area to the 
level of the sea-shore. So that, if a small- 
fraction of the layer of fine earth, -2 of an 
inch in thickness, which is annually brought 
to the surface by worms, is carried away, a 
great result cannot fail to be produced within 
a period which no geologist considers ex- 
tremely long. 

Archaeologists ought to be grateful to 
worms, as they protect and preserve for ai> 



812 CONCLUSION. CHAP. VII. 

indefinitely long period every object, not 
liable to decay, which is dropped on the 
surface of the land, by burying it beneath 
their castings. Thus, also, many elegant and 
curious tesselated pavements and other ancient 
remains have been preserved ; though no 
doubt the worms have in these cases been 
largely aided by earth washed and blown 
from the adjoining land, especially when cul- 
tivated. The old tesselated pavements have, 
however, often suffered by having subsided 
unequally from being unequally undermined 
by the worms. Even old massive walls may 
be undermined and subside ; and no building 
is in this respect safe, unless the foundations 
lie 6 or 7 feet beneath the surface, at a depth 
at which worms cannot work. It is probable 
that many monoliths and some old walls have 
fallen down from having been undermined 
by worms. 

Worms prepare the ground* in an excel- 
lent manner for the growth of fibrous-rooted 
plants and for seedlings of all kinds. They 

* White of Selborne has some good remarks on the service 
performed by worms in loosening, &c., the soiL Edit, by 
L. Jenyns, 1843, p. 281. 



CHAP. VII. CONCLUSION. 313 

periodically expose the mould to the air, and 
sift it so that no stones larger than the par- 
ticles which they can swallow are left in it 
They mingle the whole intimately together, 
like a gardener who prepares fine soil for his 
choicest plants. In this state it is well fitted 
to retain moisture and to absorb all soluble 
substances, as well as for the process of nitri- 
fication. The bones of dead animals, the 
liarder parts of insects, the shells of land- 
molluscs, leaves, twigs, &c., are before long 
all buried beneath the accumulated castings of 
worms, and are thus brought in a more or 
less decayed state within reach of the roots 
of plants. Worms likewise drag an infinite 
number of dead leaves and other parts of 
plants into their burrows, partly for the sake 
of plugging them up and partly as food. 

The leaves which are dragged into the bur- 
TOWS as food, after being torn into the finest 
shreds, partially digested, and saturated with 
.the intestinal and urinary secretions, are com- 
mingled with much earth. This earth forms 
the dark coloured, rich humus which almost 
everywhere covers the surface of the land 
with a fairly well-defined layer or mantle. 



314 CONCLUSION. CHAP. VIT. 

Hensen* placed two worms in a vessel 
18 inches in diameter, which was filled with 
sand, on which fallen leaves were strewed ; 
and these were soon dragged into their bur- 
rows to a depth of 3 inches. After about 
6 weeks an almost uniform layer of sand, a 
centimeter (*4 inch) in thickness, was con- 
verted into humus by having passed through 
the alimentary canals of these two worms. 
It is believed by some persons that worm- 
burrows, which often penetrate the ground 
almost perpendicularly to a depth of 5 or 6 
feet, materially aid in its drainage ; notwith- 
standing that the viscid castings piled over 
the mouths of the burrows prevent or check 
the rain-water directly entering them. They 
allow the air to penetrate deeply into the 
ground. They also greatly facilitate the 
downward passage of roots of moderate size ; 
and these will be nourished by the humus 
with which the burrows are lined. Many 
seeds owe their germination to having been 
covered by castings; and others buried to 
a considerable depth beneath accumulated 
castings lie dormant, until at some future 

* ' Zeitschrift fur wissenscbaft. Zoolog.' B. xxviii. 1877, p. 36(X 



CHAP. VII. CONCLUSION. 315 

time they are accidentally uncovered and 
germinate. 

Worms are poorly provided with sense- 
organs, for they cannot be said to see, 
although they can just distinguish between 
light and darkness ; they are completely deaf, 
and have only a feeble power of smell ; the 
sense of touch alone is well developed. They 
can therefore learn but little about the outside 
world, and it is surprising that they should 
exhibit some skill in lining their burrows 
with their castings and with leaves, and in 
the case of some species in piling up their 
castings into tower-like constructions. But it 
is far more surprising that they should ap- 
parently exhibit some degree of intelligence 
instead of a mere blind instinctive impulse, in 
their manner of plugging up the mouths of 
their burrows. They act in nearly the same 
manner as would a man, who had to close a 
cylindrical tube with different kinds of leaves, 
petioles, triangles of paper, &c., for they 
commonly seize such objects by their pointed 
ends. But with thin objects a certain number 
are drawn in by their broader ends. They do 
not act in the same unvarying manner in all 



.316 CONCLUSION. CHAP. VII. 

cases, as do most of the lower animals; for 
instance, they do not drag in leaves by their 
foot-stalks, unless the basal part of the blade 
is as narrow as the apex, or narrower than it. 

When we behold a wide, turf-covered 
-expanse, we should remember that its smooth- 
ness, on which so much of its beauty depends, 
is mainly due to all the inequalities having 
been slowly levelled by worms. It is a mar- 
vellous reflection that the whole of the super- 
ficial mould over any such expanse has passed, 
and will again pass, every few years through 
the bodies of worms. The plough is one of 
the most ancient and most valuable of man's 
inventions; but long before he existed the 
land was in fact regularly ploughed, and still 
continues to be thus ploughed by earth-worms. 
It may be doubted whether there are many 
other animals which have played so important 
;a part in the history of the world, as have 
these lowly organised creatures. Some other 
animals, however, still more lowly organised, 
namely corals, have done far more conspicuous 
work in having constructed innumerable reefs 
and islands in the great oceans ; but these are 
almost confined to the tropical zones-. 



INDEX. 



Abinger, Eoman villa at, 180 

, castings from Eoman villa at, with rounded 

particles, 256 

Acids of humus, action on rocks, 242 
Africa, dust from, 237 
Air, currents of, worms sensitive to, 29 
Amount of earth brought to the surface by worms, 131 
Ants, intelligence of, 95 
Archiac, D', criticisms on my views, 4 
Artemisia, leaves of, not eaten by worms, 34 
Ash-tree, petioles of, 81 

Beaulieu Abbey, burial of the old pavement, 195 
, castings from, with rounded particles, 

258 

Beaumont, Elie de, on vegetable mould, 2 
' on the rubbish underlying great cities, 

180 

on the transport of dust, 239 

on the permanence of mould, 292 

on the permanence of ancient tumuli, 



293 

Beech-forests, stones not buried under by castings, 146 
Bengal, worms of, 125 
Boa-constrictor lubricating its prey, 44 
Bones, crushed, burial of, under castings, 148 
JBrading, Koman villa at^201 



318 INDEX. 

Brading, castings from, with rounded particles, 257 
Bridgman, Mr., on worms eating leaves of a Phlox, 34 
Buckman on grasses profiting by being rolled, 10 
Burial of the remains of ancient buildings by worms,, 

178 
Burrows, depth of, 111 

direction of, on a slope, 273 

excavation of, 100 

lined with black earth, 113 

lined with leaves, 114 

mouths of, worms lie motionless near, 15 

old, their collapse, 120 

plugged up, 60 

terminating in a small chamber, often lined with, 

stones or seeds, 116 

Calciferous glands, 17, 45 
Cannibal worms, 37 
Carabus attacking worms, 65 
Carnagie, Mr., depth of burrows, 116 
Castings, acid, 53 

from Beaulieu, 103 

in cellars, 107 

tower-like, near Nice, 108 

ejection of, 118 

tower-like, from near Calcutta, 125 

of great size on the Nilgiri Mountains, 128 

weight of, from a single burrow and from a given 

area, 163 

thickness of layer formed from, during a year, 171 

ejected over ancient buildings, 256 

flowing down slopes, 264 

washed away, 275 

dry, disintegration of, 278 

blown to leeward, 286 



INDEX. 319 

Cellars, castings in, 107 

Cells, free, with calcareous matter in the calciferous 

glands, 48 

Cellulose, digestion of, 38 
Chalk-formation, surface of, much denuded, 139 
Chalk, residue of, forming a superficial deposit, 140 

fragments of, soon buried and corroded, 141 

formation of mould over, 300 

Ched worth, Roman villa of, 199 

Circular trenches near Stonehenge, 290 

Claparede on the structure of the intestines of worms, 19 

on the salivary glands of worms, 44 

on the calciferous glands, 45 

on the pharynx adapted for suction, 58 

doubts whether earth serves worms as food, 

104, 107 

on the gizzards of worms, 249 

Clematis, petioles of, used in plugging up burrows, 60, 

80 

Cobra-snake, intelligence of, 96 
Collapsing of old burrows, 120 
Concluding remarks, 308 
Concretions of lime in the anterior calciferous glands, 47 

calcareous, use of, 55 

Corals, mud derived from, 259 

Corniche road, disintegrated castings on, 279, 284 

Croll, Mr., on denudation, 235 

Crowns or ridges on old ploughed fields, 295 

Currents of air, worms sensitive to, 29 

Dancer, Mr., on the action and number of worms, 148, 

162 

Deafness of worms, 26 

Debris over the Roman remains at Silchester, 203 
Decay of leaves not hastened by the secretion with which 

they are bathed, 39 



320 INDEX. 

Denudation of the land, 232 
Depth to which worms burrow, 111 
Digaster, 249 
Digestion of worms, 38 

extra-stomachal, 44 

Disintegration of rocks aided by worms, 238 

Distribution of worms, 122 

Down, amount of earth here brought annually to the- 

surface, 139 

Downs near Winchester, valleys in, 304 
Dust, distance transported, 237-239 

Earth, amount of, brought to the surface by worms, 
131 

amount of, which flows down a given slope, 269 

swallowed as food, 102 

weight of, ejected from a single burrow, 163 

Eisen on the number of species of worms, 9 

on the depth of burrows, 112 

Ejection of castings, 118 
Embankments on hill-sides, 281, 285 
Encampments, ancient, 293 
Ernst, Dr., on worms at Caracas, 123 
Excavation of the burrows, 100 

Fabre, M., on the instincts 'of Sphex, 95 

Farrer, Mr. T. H., on the Roman villa at Abinger, 

180-190 

Fat eaten by worms, 38 
Fields formerly ploughed, 295 
Fish, Mr., criticisms on my views, 6 
Flints standing vertically in the residue over the chalk, 

140 
acted on externally and internally by atmospheric 

agencies, 248 



INDEX. 321 

Flowing down of castings, 264 
Fluid, digestive, of worms, 38 
Food of worms, leaves, 36 

earth, 102 

Foster, Michael, on the pancreatic ferment, 38 
on the acidity of the contents of tliO' 

intestines, 53 
Foundations, deep, of the Eoman buildings at Wroxeter, 

229 

Fredericq, Leon, on the digestive juice of worms, 38 
Furrows on old ploughed fields, 295 

Galton, Mr., on the number of dead worms, 14 
Geikie, Archibald, on Denudation, 235 

controverts ~E. de Beaumont's views on 

Denudation, 292 

, James, controverts Kichthofen's views, 239 

on glaciated rocks, 248 



Geographical distribution of worms, 122 

Gilbert, Dr., on the amount of nitrogen in worm-castings,, 

244 

Gizzards of worms, 249 
Glands, calciferous, 17, 45 

function of, 50 

Glen Boy, evidence of rarity of debacles, 263 

Haast, Von, on aboriginal instruments in New Zealand 

found buried, 150 
Hearing, sense of, 26 
Heat, perception of, 25 
Heaths, inhabited by few worms, except where patb 

cross them, 10 
Hensen on the number of worms in gardens, 5 

on worms not subsisting on earth, 110 

on the depth of burrows, 112 



322 INDEX. 

Hensen on number of worms living in a given area, 161 

on the composition of mould, 240 

on the amount of humus formed by two 

worms, 314 

Henslow, Prof., on ledges on hill-sides, 281 
Hoffmeister, number of species of worms, 9 

on worms hybernating in company, 35 

perception of light by worms, 20, 22 

on the enemies of worms, 65 

depth of burrows, 112 

on hybernation of worms, 116 

Hooker, Sir J., on ledges of earth on the Himalaya, 281 
Horner, Mr., on castings in a cellar, 108 
Humus acids, action of, on rocks, 242, 247 

Instinct of worms, 36 
Intelligence of worms, 36, 66 
Intestines of worms, their contents acid, 52 
Islands inhabited by worms, 122 

Johnson, Dr. H., on the Roman remains at Wroxeter, 
224-230 

on ammonia in worm-castings, 244 

Johnson, S. W., * How Crops Feed,' 244 
Joyce, Rev. J. G., on the Roman remains at Silchester, 203 
Julien, Mr. A. A., on the composition of peat, 240 
on the humus-acids, 242, 247 

Key, Rev. H., on the burial of cinders by worms, 148 
King, Dr., on the formation of mould in forests in 

France, 5 

on castings near Nice, 108, 119 

on great castings on the Nilgiri Mountains 

and in Ceylon, 128 
weight of castings near Nice, 165 



INDEX. 323 

King, Dr., on disintegrated castings on the Corniche 

road, 279, 284 
on the washing away of the castings on the 

Nilgiri Mountains, 277 

Knole Park beech- woods, worms absent from, 12 
Koninck, De, on the disintegration of rocks, 237 
Krukenberg on the digestive fluid of worms, 38 

Laburnum leaves, 70 

Land, denudation of, 232 

Lankester, Bay, on the structure of worms, 18 

on worms from Kerguelen Land 123 

La Plata, dust storms of, 238 

Layard,Mr., on the habits of the cobra, 96 

Leaves, worms distinguish the taste of different kinds of, 33 

consumed by worms, 36 

their decay not hastened by the alkaline secretion 

with which they are bathed, 39 

decayed, generate acids, 52 

used in plugging up burrows, 67 

used to line burrows, 114 



Ledges of earth on hill-sides, 281 
Light, perception of, by worms, 20 
Lime, carbonate of, concretions of, 46 

Maer Hall, amount of earth brought to surface, 132 
Mallett, Mr., on the sinking of the ground under great 

buildings, 161 

Meat, raw, eaten by worms, 37 
Mental qualities of worms, 34 
Mint, leaves of, only nibbled, 34 
Mississippi, drainage area of, 235 
Moles pursuing worms, 28 
Mobius on the habits of a pike, 96 
Moniligaster, 249 



324 INDEX. 

Moot-house, Mr., on peewits beating the ground, 28 

JVIorren on worms surviving long immersion, 13 

OH worms lying motionless near mouths of their 

burrows, 15 

on worms eating sugar, 37 

on the disappearance of the calciferous glands 

during winter, 50 

on stones in the gizzards of worms, 250, 252 

Mould, thickness of, annually ejected by worms, 171 
thickness of, over Eoman remains at Chedworth. 

201 

nature and thickness of, over the Roman remains 



at Silchester, 220 

thickness of, at Wroxeter, 225 

formation and thickness of, over the chalk, 800 

Mountains, worms absent from, 12 

Miiller, Fritz, on the worms in South Brazil, 124 

Miiller, P. E., on earthworms, p. 7. 

Nice, castings near, 108 

disintegrated castings near, 279 

Night, worms leave their burrows at, 14 
Nilgiri Mountains, castings on, 128 

Objects strewed on the surface soon buried under cast- 
ings, 132 

Obliteration of old furrows on ploughed land, 295 
Odours, degree of sensitiveness to, by worms, 30 

Pancreatic secretion, 38 

not acid, 54 

Paper, triangles of, 85 

Parfitt, Mr., on the closing of the mouths of burrows, 65 

Path, paved, burial of, by worm-castings, 147 

Paths inhabited by worms, 10 

Pavement, modern, undermined by worms, 194 



INDEX. 325 

Pavements, ancient, subsidence of, at Sil Chester, 214 
Peat, formation of, 241 
Peewits beating the ground, 28 
Percolation of earth into the chalk, 300 
PerichsBta, naturalized near Nice, 108 
Perrier, worms surviving long immersion, 13 

on the calciferous glands, 45 

on the action of the pharynx, 58 

on the burrowing power of worms, 101 



on naturalized worms, 108 

on worms killed by acetic acid, 162 

on the gizzards of worms, 249, 252 



Petioles of Clematis, 80 

of the ash, 81 

Pharynx, action of, 58 

Pike, stupidity of, 96 

Pine-leaves used in plugging up burrows, 61, 73 

lining burrows, 114 

Pipes, formation of, in the chalk, 139 
Playfair on Denudation, 293 
Ploughed fields, old, 295 
Plugging up of the burrows, 60 

use of the process, 64 

Prehension, power of, by worms, 58 

Qualities, mental, of worms, 34 

Eamsay, Mr., on the sinking of a pavement undemined by 
worms, 194 

on Denudation, 233 

Eemains, ancient, buried by worms, 178 

Rhododendron leaves, 71 

Richthofen on dust deposits in China, 239 

Robinia, petioles of, 83 

Rocks, disintegration of, aided by worms, 238 



326 INDEX. 

Rocks, triturated in the gizzards of worms, 252 

Rolling down of dry castings, 278 

Romanes, Mr., on the intelligence of animals, 97 

Sachs on living roots corroding rocks, 245 

Sage, leaves of, not eaten by worms, 34 

Saliva, doubtful whether any secreted by worms, 44- 

Saussure, H. de, on brick-pebbles, 257 

Schmulewitsch on the digestion of cellulose, 39 

Scolopendra attacking worms, 65 

Scott, Mr. J., on worms near Calcutta, 125 

Seeds preserved in the burrows of worms, 117 

Semper on various animals swallowing sand, 104 

Senses of worms, 19 

Silchester, old Roman town, 203 

Silica, colloid, acted on by the humus-acids, 244 

Simpson, Mr., on worms dragging leaves, 60 

Sinking of the pavements at Silchester, 214 

Sites inhabited by worms, 9 

Smell, sense of, 29 

Social feelings of worms, 35 

Sorby, Mr., on the trituration of small particles of 

rock, 260 

Stanley on peewits beating the ground, 28 
Starch eaten by worms, 37 
digestion of the granules in the cells of leaves, 

43 

St. Catherine's Hill, near Winchester, 305 
Stones, great, undermined by worms at Leith Hill and at 

Stonehenge, 151 

small, heaped over burrows, 63 

small, in the gizzards of worms, 250 

rounded in the gizzards of worms, 252 

Stonehenge, great stones of, undermined by worms, 157 
circular trenches near, 290 



INDEX. 327 

Structure of worms, 16 

Sturtevaiit, Dr., on worms found coiled together, 35 

Subsidence of the pavements at Silchester, 214 

Suction, power of, 58 

Sugar eaten by worms, 37 

Summary of whole book, 308 

Surface, objects strewed on, buried under castings, 132 

Taste, power of, 33 

Thickness of the layer of mould annually ejected by 

worms, 171 

of the mould over the remains at Chedworth, 201 

of the mould over the remains at Silchester, 220 

of the mould over the Roman remains at 

Wroxeter, 225 

Thyme, leaves of, not eaten by worms, 34 
Touch, worms highly sensitive to, 29 
Triangles of paper, 85 
Trituration of particles of rock in the gizzards of worms, 

252 

Tumuli, ancient, 293 
Tylor, Mr. A., on Denudation, 235 
Tylor, Mr. E., on anciently ploughed land, 296 
Typhlosolis, 19 

Utricularia, bladders of, 111 

Vibrations, worms sensitive to, 27 
Vision, power of, in worms, 20 

Wallace, Mr. J., on worm-burrows, p. 270. 

Walls, ancient, at Abinger, penetrated by worms, 190 

penetrated by worms at Silchester, 211 

Washing away of castings, 275 

Wedgwood, Mr., on the formation of mould, 3 



328 INDEX. 

Weight of earth ejected from a single burrow, 163 

Whitaker, Mr., on Denudation, 234 

White on worms leaving their burrows at night, 14 

Winchester, chalk formation near, 304 

Wind, action of, on castings, 286 

Worms, nocturnal, 13 

large numbers occasionally die, 14 

dead eaten by other worms, 34 

contents of intestines acid, 52 

their castings acid, 53 

power of suction, 58 

plugging up their burrows, 60 

intelligence of, 66 

formation of their burrows, 100 

number of, living in a given area, 161 

penetrating ancient walls, 190, 211 

gizzards of, and the trituration of the contained 

stones, 249 

prefer to live in fine earth, 294 

Wright, Mr., on the age of Wroxeter, 223 
Wroxeter, old Roman town of, 223 

Zincke, Rev. F. B.. on celts found at a depth of thrco 
feet, 148 



PRINTED BY WILLIAM CLOWES AND SONS, LIMITED 
STAMFOBD STREET AND ClUEINO CBOSS. 



Date Due 



MAY 2 



31972 



CAT. NO. 23 233 PRINTED IN U.S.A. 



REGIONAL LIBRARY FACILITY 



A 000500919 6 



QH365 
.Al 

1897 
Darwir . 

The formation of vegetable mould, 



CALIFORNIA COLLEGE OF MEDICINE LIBRARY 

UNIVERSITY OF CALIFORNIA, IRVINE 

IRVINE, CALIFORNIA 92664