794 
Supplement to the " Tropical AgricuUwist." [May 1, 1900. 
Experience has shown that whether nitrates are 
formed in the soil by the action of micro-organ- 
ism, or introduced in the form of fertilisers, they 
exert a decided influence upon the crop. Nitrates 
are not formed in soils like tliose of meadows or 
forests, which are highly chnrged with decaying 
organic matter, since tliese soils are acid and 
therefore do not furnish a suitable medium for 
the nitric ferment. Liming renders such soils 
more favourable to the activity of the nitric 
organisms. 
In meadow and forest soils nitrogen appears to 
be taken up by plants in the form of ammonia. 
Br6al has shown that nitrogen is also taken up by 
plants in the form of luimates of lime or potash, 
Hellriegel has shown in experiments with barley 
fertilised with variable amounts of nitrates that 
the amount of water transpired by the plant per 
gram of dry matter increases as the amount of 
nitrates applied decreases. Barley, which receiv- 
ed the most favourable amount of nitrates, eva- 
porated 260 gm, of water pnv gram of dry matter 
produced. The plants which received no nitrates 
and which made a sickly growth evaporated from 
700 to 800 gm, of water per gram of dry matter. 
Normal, vigorous plants obviously evaporate more 
water than sickly ones, but if we calculate the 
ratio of the quantity of water transpired to the 
weight of dry matter produced we find that the 
proportion is greater in the sickly than in the 
vigorous plants. This fact may be useful in 
determining the efficacy of a fertiliser. 
By pursuing this method of investigation the 
author found tliat the Gramineae and Leguminosae 
do not take up and utilise plant food in the same 
manner. The Graminese are especially benefited 
by chemical fertilisers, particularly nitrates, 
while they do not utilise humus substances to 
very great advantage. On the other hand, Legu- 
minosse are more benefited by the humates than 
by nitrates or ammonia salts. 
Rye grass and clover were planted in large pots, 
each of which contained 50 kg. of soil exhausted 
by continuous cropping. Equal amounts of phos- 
phoric acid, potash, and nitrogen were applied. 
In one case the nitrogen was applied in the form 
of nitrates, in the other in the form of humate, 
A black extract from manure which contained a 
mixture of humate of potash and humate of 
ammonia was also used. At the end of the ex- 
periment it was found that the rye grass which 
had received no manure had transpired 682 gm. 
of water per gram of dry matter, that which had 
received hunwites 435 and 469 gm., and that which 
had received only chemical fertiliser 233 gm. 
The results were quite different with clover. In 
this case the transpiration was : without manure 
454 gm., with chemical fertilisers 398 gm., and 
with humates 272 and 265 gm. These results 
confirm the conclusions of Br6al, Snyder, and 
Lawes and Gilbert. The latter have shown at 
Rothamsted that it was impossible to grow clover 
continuously on the same land unless the soil was 
abundantly supplied with organic manures. 
To summarise, then, nitrogen is taken up by 
plants in the form of nitrates, ammonium salts, 
and alkaline humataa. The Leguminosae can 
utilise free nitrogen only when it has been brought 
into combination by the action of the organisms 
of^the root tubercles. It has frequently beea 
claimed that other plants besides the Legumj* 
nosae are capable of absorbing free nitrogen, but 
it has been shown that this absorption does not 
take place without the intervention of the organ- 
isms which fix nitrogen. 
THE BANANA AS AN ARTICLE OP FOOD. 
[Specially translated foe " Indian 
Cabdening" feom the Belgique Coloniale.'] 
In the Congo country, and in almost all tropical 
countries, the Banana constitutes an important 
resource of food for European and native alike. 
Hardly is a new station or village formed than a 
Banana plantation is started to ensure, after a 
brief period, food in abundance. 
The Banana is very nutritious and forms almost 
a complete sustenance ; it contains more than 2.5 
per cent, of assimilable organic matters. According 
to Humboldt, it is 48 times more nuritious than 
potatoes; and according to Crighton Campbell, 
the apostle of the diffusion of the Banana in 
America, it is 28 times as nutritious as the best 
wheaten bread. 
The negroes occasionally consume Banana meal, 
which they prepare in an altogether primitive 
manner. They dry the fruits and pound them in 
a morcar. Placed in jars or sacks, away from 
damp, this meal remains good for a long time. It 
is also very nourishing and used especially on 
journeys, A very healthy and refreshing drink is 
made from it. In Central America, Columbia and 
Venezuela, Banana meal is made on a great scale. 
For the preparation of Banana meal the fruit is 
stripped of its skin and cut in rounds, which are 
placed in a drying apparatus. After it is com- 
pletely dry, it is ground and passed through a sieve. 
The production of meal is from 20 to 25 per cent. 
An amount of raw material 15 lbs. in weight gives 
3 lbs. of meal. 
In order to obtain more exact ideas of the 
nutritive value of Banana meal. Dr. Thoms, 
Director of the Laboratory of Pharmaceutical 
Chemistry at the University of Berlin, has analysed 
it. It contains 1'455 per cent, of nitrogen, 
corresponding to 9"01. per cent, of nitrogenous 
matter. In consequence, the nutritive valu» of 
Banana meal is very great and sensibly approaches 
that of the best wheat flours, which do not contain 
more than 9 to 11 per cent, of nitrogenous matter. 
For the manufacture of meal, it is preferable to 
use fruit which is not altogether ripe, as the 
starch which is contained changes to sugar in a 
measure as it arrives at maturity. For the rest, 
the following results of analysis show its value 
abundantly : — 
Unripe Ripe 
Bananas, 
Bananas. 
Water 
... 70-92 
67-78 
Starch 
... 12-06 
Traces 
Grape Sugar ... 
... 0-08 
20-47 
Cane Sugar ... 
... 1-34 
4-60 
Fat 
.. 0-21 
0-58 
Nitrogenous 
matter 
... 304 
4-72 
Crude fibre ... 
... 0-o6 
017 
Tannin 
... 6-53 
0-34 
Ash 
... 1-04 
095 
Other matters 
... 4-62 
0-79 
