254 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ September 18,1890, 
large scale. The Yoruba Indigo yielded by Lonchocarpus cyanescens, 
Benth., is described in the Kew Bulletin for November, 1888, p. 268, 
with a figure of the plant. Yoruba Indigo sent to Kew by Sir Alfred 
Moloney was valued in 1883 at 4s. to 4s. 6d. per lb. It is possible that 
this sort might be more successful in West Africa than the ordinary 
Indigo. The natives are accustomed to the preparation of it, and it is 
only necessary to eliminate the earthy matter and portions of the stems 
usually found in Yoruba Indigo to produce samples worth nearly as 
much as the best Bengal Indigo. 
Vanilla and Pimento are valuable spices, but probably not every¬ 
where suited to the soil and climate of West Africa. They might, 
however, flourish inland where it is damper and moister, and it would 
be well on this account to keep them under observation and increase the 
Btock in view of future action. 
It is a little doubtful whether the Cacao or Chocolate will eventually 
justify the hopes at present entertained respecting it. Although the 
plants survive the dry seasons it is possible that they may not ultimately 
yield remunerative crops. On the other hand, in sheltered valleys 
inland and in damp localities free from prolonged droughts Cacao 
should do very well. Next to Coffee, fibres, Egyptian Cotton, and 
spices, I would regard Cacao or Chocolate as a most promising and 
reliable industry for West Africa if only the right soil and climate are 
found for it. Tea may be tried, and also Tobacco, but unless an expert 
is engaged to grow and prepare the produce there is no hope of 
establishing a permanent industry to supply European markets with 
either of these at present. 
It may be very well worth while to try and establish the Ceara 
Rubber (Manihot Glaziovi) in West Africa. It has apparently 
established itself at the Gambia in very poor sandy soil and under very 
arid conditions. It requires little attention, and yields rubber at an 
early period. It very much resembles the Cassava plant in habit and 
requirements, and as the natives already cultivate the latter they would 
be likely to take very readily to the rubber plant. Seed of the Ceara 
rubber could be obtained in quantities from Ceylon. 
The cultivation of fruits in West Africa might be greatly extended, 
if only for local demands. Pine Apples, Bananas, Guavas, Oranges, 
Limes, Mangoes, Bread-fruit, Custard Apple, Avocado Pear, Tamarind, 
Granadilla, Papaw, Water Melons, are already found growing at or near 
most of the Settlements, Little or no attention is, however, devoted to 
their systematic culture, and hence the yield and quality are below 
what they ought to be. It may be found ultimately practicable to 
export some of the fruits in a fresh or preserved state to this country. 
An account of West African fruits and the production of each at Sierra 
Leone, Gold Coast, and Lagos is given in the Kew Bulletin for October, 
1888, pp. 221-224. 
In reports which have reached Kew from West Africa considerable 
stress is laid upon the difficulty of keeping plants alive during the dry 
season. It is evident that a continuous supply of fresh water, easily 
accessible to nurseries and plantations, is of the highest importance 
Water should be abundantly provided by means of small irrigation 
channels all over plantations in dry districts, with holes oi wells here 
and there to facilitate watering any plants that require it. The saving 
in labour under such circumstances would be very considerable. Shelter 
trees should be planted, where they do not already exist, to protect the 
plantations from winds and to shade such plants as require it from the 
direct rays of the sun. 
There are several species of Figs in West Africa that are admirably 
adapted to this purpose. Live fences made of such plants as Logwood 
and the Madras Thorn (Inga dulcis) would protect the plantations and 
afford some relief from dry winds. The Logwood is a tree of great 
promise for West Africa. Seeds of Logwood could easily be obtained 
from the West Indies, while seeds of the Madras Thorn might be got 
from Ceylon or India. 
The question of soil should receive the most careful attention. A 
rich loamy soil of good depth, with good natural drainage and within 
easy reach of water, is most essential for cultivated areas. There should 
be considerable time spent over the selection of sites for plantations, and 
every point should be carefully considered before the site is ultimately 
settled.— D. Morris (in Kew Bulletin for September). 
THE LIVING EARTH. 
In connection with the recent Congress at Brighton held by the 
Sanitary Institute, Dr. G. V. Poore, M.D., F.R.C.P., who is President of 
section I., presided over the meeting of that section, and delivered an 
address on “.The Living Earth,” the substance of which is given in the 
following paragraphs. 
Sanitation in large cities is, at the best, a makeshift, and no high 
level of health is attainable in a place where the chief object of 
hygienists seems to be to enable persons to live as densely packed as 
possible. This prelude is necessary, because the remarks which I am 
about to make are addressed mainly to persons who live in the country, 
and who enjoy the luxury of elbow room, and I trust that what I am 
about to say will make them hesitate before they hastily copy the 
sanitary methods of the town, and heedlessly begin to foster overcrowd¬ 
ing, the bane of all sanitary and social virtue. I say that my remarks 
are addressed to dwellers in the country, because I have taken for my 
subject the “ Living Earth,” a subject which those who live on paving 
stones, tarred blocks, asphalte, or macadam have to take upon trust. 
The “ Living Earth 1” Some of you may ask what I mean by this, and 
whether I intend to apply the epithet “ living ” to the dark coloured 
inert mould which the countryman sees in the fields and gardens, and 
the town dweller finds in the flower pot which holds his struggling 
Geranium ? My reply is, “ Certainly.” We have arrived of late years 
at a certain knowledge of the fact, that the mould which forms the 
upper stratum of the ground on which we live is teeming with life, and 
as this fact seems to me to be one of prime importance to sanitarians, I 
propose to bring some points in connection therewith before you this 
morning. 
It has long been recognised by agriculturists that the upper stratum 
of the soil differs from that immediately below it in fertility ; and in 
treatises on gardening (notably in that admirable work written by 
William Cobbett nearly seventy years since) the warning is invariably 
given to be careful, in trenching, not to bury the top spit of soil beneath 
the lower spit, because the top spit is by far the most fertile. The fer¬ 
tility in this case was supposed to be due to prolonged exposure to air, 
and the lower stratum of soil, if brought to the surface, would only 
become fertile after a considerable interval. It is interesting to observe 
that although these early writers were unacquainted with the whole 
truth they had grasped the most important fact, and their practice was 
sound. This is often the case, and I feel sure that we act rashly when 
we hastby abindon the custom of centuries, because some new fact 
dazzles us and distorts our vision. In connection with William Cobbett 
I will draw attention to a term which he uses more than once in the 
work referred to, viz., the fermentation of the soil. I have not found 
this expression employed by any other writer, but I have made no 
special search, and my knowledge of agricultural authors is limited. 
Cobbett tells us that the earth begins to ferment in the spring, and that 
before sowing a thorough tilling and mixing of the upper strata of the 
soil is very necessary, with a view not only to the disintegration of the 
soil, but to a thorough leavening of the whole mass with fermentible 
matter. There is no doubt that this term “ fermentation.” as applied to 
the soil, is perfectly apt, as we shall find further on. The black vege¬ 
table mould which lies upon the surface of the earth is largely com¬ 
posed of organic matter, which is not to be wondered at, seeing that every 
organised thing, whether animal or vegetable, which inhabits this globe 
falls, when dead, upon the earth, and becomes incorporated with it. 
Darwin, in his book on “ Vegetable Mould and Earthworms,” has for¬ 
cibly drawn attention to the enormous amount of work which worms 
perforin in the aggregate. How they disintegrate the soil. How they 
riddle it with burrows, which admit air to the deeper recesses of the 
soil. How their castings, which are incessantly being thrown off, tend 
to level inequalities, and gradually to bury stones or whatever dead in¬ 
organic matter is incapable of solution, digestion, or disintegration. 
Earthworms are found almost everywhere, and they are probably the 
most important of the animals which live in the soil ; but I need 
scarcely say that there are many others, and everyone who has a 
garden must reeognise the fact that gardening is only carried out at an 
enormous sacrifice of animal life, for with every thrust of the spade 
into rich garden mould a death blow is dealt to many of its inhabitants. 
The disintegration and aeration of the soil, which is effected by the quiet 
tillage of the earth-dwellers, is of the greatest importance to the agri¬ 
culturist, for it is hardly conceivable that the delicate rootlets of plants 
could grow and extend unless the soil had been softened and pounded 
by the earthworms and their neighbours. 
Although the amount of animal life in the earth is considerable, it is 
nothing compared with the richness of the soil in the lower forms of 
vegetable life. The dead and excremental matter becomes the food of 
saprophytic fungi, which abound in the soil to a very great extent. 
This must be the case, for we know that saprophytes and their allies 
abound everywhere, and as the surface of the earth is the common reser¬ 
voir of all forms of life, it follows that these low vegetable microbes 
must be more abundant in the earth than elsewhere, and more abundant 
at the surface than deeper down. In Watson Cheyne’s edition of Fliigge’s 
work on micro-organisms (New Sydenham Society, 1890), this is very 
clearly stated : “ Enormous numbers of bacteria have always been found 
in the soil by the most various observers. Infusions made from manured 
field and garden earth, even though diluted 100 times, still contain thou¬ 
sands of bacteria in every drop, and the ordinary soil of streets and courts- 
also shows the presence of large numbers. Bacilli are present in much 
the largest numbers ; but in the most superficial layers and in moist 
ground there are also numerous forms of micro-cocci.” These micro¬ 
organisms of the soil are very active in producing changes in organic 
matter added to the soil. These changes are usually in the direction of 
oxidation ; occasionally the change is one of reduction. One thing is 
certain, that if the soil be sterilised by heat or other means it is no 
longer capable of producing any chemical change in organic matter. 
This seems to me to be a fact of prime importance to the sanitarian. 
The oxidation and nitrification of organic matter in the soil is a biological 
question, pure and simple. It is an effect produced by the living earth ; 
a process analogous to fermentation, which Cobbett seems to have appre¬ 
ciated. Whether the nitrifying process which takes place in the soil is 
due to one or to many varieties of microbe is doubtful, but the latter 
supposition is probably correct, and experiments seem rather to point to 
the conclusion that, given favourable conditions—the free admission of 
air to a soil which is not unduly moistened—nitrification will go on. 
Many attempts have been made to isolate a nitrifying organism, and one 
of the latest, by Professor Percy Frankland and Grace Frankland, the 
results of which were communicated to the Royal Society in February 
1890, appears to have been successful, for these observers isolated 
a “ bacillo-coccus,” the power of which in producing nitrification 
