22G 
Supplement to the " Tropical Agriculturist." 
[Seit. 1, 1898. 
that i?, eleven days after inoculation witli bile; 
(e) L Jv 2 received 20 c cm. of the same blood 
on the same date and under the same conditions. 
All these animals proved to be immune. 
The dose of virulent blood used in tliese^test 
cases is said by Koch to be respectively o,000 
and 10,000 times greater than a fatal dose. 
The expeiiments above recorded go to show 
that Professor Koch's preventive treatment with 
bile promises to be successful in Bengal. The 
exact amount of success can only be determined 
by future experiment. 
Here again Mr. (i. R, Toomey has rendered 
great assistance by permitting the inoculated 
bullocks to be branded, so that each animal 
might be identified later. 
I have performed another experiment to ascertain 
if by any chance bile in this province would 
confer immunity quicker than in other climates. 
For this pu'pose 1 injected calves with 10 c. cm. 
of bile and five days later tested them with 
virulent blood from Buffalo No- 5. They have all re- 
acted in temperature, three developed genuine 
rinderpest, and one died. 
Experiments are proceeding." 
THE RELATION OF WATEll TO SOIL 
FERTILITY. 
It is evident that as regards fertilizers there is 
an opportunity for selection with reference to 
special conditions which will greatly influence 
the profit from their use. 
Declaux has said that " the meteorology of a 
reciou influences the vegetation more than the 
o-eology," and under different climatic conditions it 
is to be expected that fertilizers will give different 
results, so that the results of fertilizer experiments 
in one place cannot be expected to be the same in 
another. 
The life of a plant is in effect the resultant of a 
number of physical conditions acting in con- 
junction. For example, the action of water will 
not be the same during a hot and a cold season 
nor in a moderately cold temperature and a 
tropical region. The exact knowledge of the 
influence of water on the phenomena of vegetation, 
therefore, requires a comparative study of this 
influence as affected by such factors as temperature, 
light, fertility of soil, &c. 
The fertilizing substances are partially absorbed 
and retained by the soil and partially dissolved. 
It is known that drainage water carries off only a 
small portion of potash, the quantity thus removed 
being least in well manured soil. The potash is 
retained not only by the humus but also by the 
clay colloids. AVith an excess of water in the soil 
the solvent action is largely increased as shown by 
the experiments of Gasparin and Berthelot and 
Andre. While the soil, therefore, may contain 
lar<ye quantities of soluble potash, it is retained 
■witii such energy that enormous quantities of 
■water are necessary to dissolve it. The solubility 
of the potash is greatly increased if some sulphate 
such as gypsum is added to the soil. Way has shown 
that the quantity of ammonia absorbed by a soil 
is nearly constant when the solutions preseut have 
the same concentration, bat tliat the force with 
which the soil absorbs alkalies varies with the 
concentration of the soluti on. Brustleiii has sliowii 
that soils are not able to remove alkali completely 
from its solution in water. Tnese solutions 
circ ulate to a considerable extent in the soils with- 
out undergoing decomposition- This explaius how 
water brings to the plant the chemicals needed ia 
very great dilution. Poiosh and ammonia are 
easilj' retained as carbonates by the soil, but less 
readily in the form of sulphates. 
When a solution of acid phopliate of lime conies 
in contact with sand, a portion of the phosphate is 
rapidly absorbed ; but absorption is not complete 
for at least twenty-five days. Still it is believed 
that there is little serious loss of phosphates by 
drainage following a heavy rain even in sandy 
soil.-, while with lime and clay soils the absorption 
is naturally more rapid and complete- 
The influence of the water of the soil upon the 
micro-organisms which play a part in the fertility 
of the soil remains to be mentioned. The experi- 
ments of Berthelot show that the nitrogen of the 
uir is fixed through bacteria in non-sterilised soil ; 
and Hallriegel and Wilfartli, Breal, Schbssing, and 
Laurent have shown that the bacteroids iu the 
root tubercles of leguminous plants are able to fix 
free nitrogen- 
It isknown that the phenomena of nitrification 
takes place in three steps — formation of ammonia, 
nitrites and nit rales — under the influence of bacteria, 
yensts, algoi and the ferments of AVinogrudsky. 
JJrtcillus Mycoidesis aerobic, and able to produce 
ammonia in the presence of organic nitrogen, but 
it becomes a denitrifier and anaerobic when there 
exists in the soil rapidly reducible substances, such 
as nitrates. 
These investigations show that the lower 
organisms play an important role in the fertility 
of the soil- Water in varying quantity has an 
influence on the biology of all these organisms. 
Schlossing and Jliintz have shown that nitrification 
requires a certain amount of moisture, and the 
writer's investigations have shown that tlie vitality 
of lihizolium ler/uminosarum is influenced by the 
water content of the soil. For each soil there is an 
optimum humidity. Too great dryness checks or 
entirely prevents the formation of tubercles. 
Excessive moisture produces an analogous effect 
though less marked. The writer has shown that 
the formation of the tubercles begins soon after 
the development of the plants, and it is therefore 
of the highest importance to furnish the young 
leguminous plant with sufficient water. 
As regards the variations in ammonia formation 
wir.h varying proportions of water, it would appear 
a priori that the results should be analogous to 
those cited in the case of nitrates. 
We think the time has arrived to study with 
greater care the absolute value of the different 
optima which are recognized in biology. It is well 
known that there are optima of temperature, of 
light, of plant-food, and of humidity with which to 
realise the best possible growth of the plant, but 
only in rare instances have the values of these 
optima been definitely fixed. It has been 
considered sufficient if we knew the optimum 
temperative for germiuatiou of our cultivated 
planta. 
