228 
Supplemetit to the " Tro/jical Agriculturist." 
[Sept. 1, 1898. 
As to the employment of any method of inocu- 
lation related to that which consists in the use of 
serum, as in dealing with animal diseases occa- 
sioned by micro-organisms, it may he stated that, 
although Dr. Eussell has concluded from experi- 
mental evidence that " vegetable cell juices, aside 
from their acid reaction, are entirely powerless 
against bacteria, and do not possess any germi- 
cidal properties like the blood serum of animals," 
the experiments that he conducted were "too 
limited in number to afford any basis for a general 
conclusion"; and there are grounds for concluding 
that " it is not improbable that a great variety of 
bactericidal and protective substances occur in 
plants," just as there are bodies contoint;d in them, 
such as " the various essential oils and other 
vegetable products — e.i/., thymol, salicylic acid, 
benzoic acid, tannin, quinine, oil of peppermint," 
&c., that are known to " exert a i)owerful res- 
training influence on bacterial growth." 
Again, there are organisms that are mot with in 
the tissues of plants in a condition referred to by 
German writers under van Beneden's term " Mutu- 
nlismus" that exert, as far as lias been ob-erved, 
no apparent influence upon either the vigour or 
development of their hosts, or if otherwii-e only 
after a comparatively long period has elapsed, 
although it has been sugge>ted tiiat the advantages 
of this " Mutualismus '' may be only distinctly 
manifested when the plant is in need of a large 
amount of nitrogenous matter — for instance, during 
the ripening of the fruit. These may yet prove 
to be destroyers of the true parasitic oigaiiisms 
occurring in plants, and therefore competent to 
prevent the maladies that these orgiiiate in them ; 
and if so, seeing tha'. plants previou.-ly free from 
their presence may be artificially infected by tliein, 
as shown by Janse and other investigators, tliey 
may be available for inoculation having for its 
end the prevention of disease. 
GENERAL ITEMS. 
There are two simple ways of ascertaining the 
height of trees. The first is well-known and 
depends on the shadows thrown, thus requiring 
the aid of the sun. The shadow of a stick fixed 
in the ground is to the length of the stick as the 
shadow thrown by the tree is to the height of the 
tree. The calculation is easily made according to 
ordinary rule of three. Another simple way 
is given in the Journal of Horticulture. Take 
three laths and nail them in the shape of a 
triangle, so that a right angle may be formed 
by two laths of equal length. Now let the 
triangle stand with one equal side along the 
ground and the other parallel with ihe tree to be 
measured. Next move the triangle into such a 
position that, as far as can be judged by 
the eye, the line opposite the right angle, if 
continued upwards will strike the top of the tree. 
It will then be seen, by the help of a diagram, that 
the height of tbe tree will be the same as the 
length of the line measured from the foot of the 
tree to the farther end of the lathe laid ou the 
ground that is to the end away from the right angle. 
An experienced cultivator of tobacco ttateg 
that the best fertilizer for the crop is crushed 
cotton seed and cotton se-;d meal. The latter to 
give the plants a q iick start, the former by its 
slow action to feed tlie plants at a later period 
and .sustain thera during the important crisis of 
leaf formation. About 80 to 100 bushels of crushed 
seed, and 500 to 800 lbs. of the meal should be 
applied per acre. 
Mr. E. Cowley writing to the Queensland Agri- 
cultural Gazette says, referring to ceara rubber, 
" the idea publi/shed in Ceylon that seeds planted' 
in fresh horse-dung will germinate rapidly has on 
triiil been quite exploded. Only six out of 100 
seeds thus planted germinated alter a^longiperiod, 
though every care was taken. Reference is also' 
made to the 'fallacy ■ that the seeds take twelve 
months to gerniinute, and it is stated that seed 
obtiiined for Messrs. Christy, Londo-i ; germiniited 
wilhin two months in the open ground without 
any preparation of teed. The writer draws atten- 
tion to the fact that half-ripened wood .'grows 
readily though older wood will not grow "at all 
except in isolated instances. The younger wood 
if friishiy planted is said to grow to a height of 
20 feet and bear flowers and fruit within 12 
months. He belie. 'cs that if rubber growing i% 
to be established in Queensland, Ceara will yield 
the best results. 
In the Stmits rubber is got from the followint; 
trees -.—Dic/iopsis c/utta, D. polyantha, li. puftu- 
lata, and D. Maiuyayi ; also from I'ayena leerii 
In Jav.i, Palagmum borneemig md 1'. qutta nre 
among the rul)bei-producing trees. A Vpeciei of 
rubber plant peculiar to Colombia, and which 
grows at an elevation of 6.000 to 8,000 ft has 
been named Sapium biglandulosum by tlie Kew 
authorities. Ficu« rigo is a rubber tree of British 
New Guinea, said to be hardy and a fost grower 
coming into " bearing " in about 4 years. ' 
Prof. Raulin of the University of Lyons has 
demonstrated that the chemical nature of the soil 
influences the seed of plants grown upon it 
and this difference may be felt for many genera- 
tions. In this way some of the widely-different 
results of experiments may be explained. 
Gaston Bounier of the University of Pdris has 
proved that in the process of acclimatization 
certain secondary characters are developed which 
are often retained by tlie plant in its struggle to 
adapt Itself to Us surroundings, this being seen in 
the convergence of morphological types under the 
influence ot cold, due either to latitude or altitude 
and the analogous structure of plants upon moun- 
tain tops nnd polar regions. 
Vesque has established the fact that inherited 
chai-acterestics have little to do with the adaptation 
Ox plants to drought, and that there is no eenus 
however small, all the species of which are 
adapted m the same degree to a given physical 
environment. f . ^ • 
