268 REPORT—1905. 
of Agriculture, finding that the bacterium will resist drying, dips strands 
of cotton-wool into an active culture medium and then dries them. The 
cotton-wool is then introduced into a solution containing maltose, 
potassium phosphate, and magnesium sulphate ; in a day or two growth 
becomes active, and the solution is distributed over soil or seed. 
It is too early yet to determine what measure of success has been at- 
tained by these inoculations with pure cultures ; but in considering the 
results a sharpdistinction must be drawn between their use on old cultivated 
Jand, such as we are dealing with in the United Kingdom, and under the 
conditions which prevail in new countries where the land is often being 
brought under leguminous crop for the first time. Few of our English 
fields have not carried a long succession of crops of clover, beans, vetches, 
and kindred plants ; the Bacteriwm radicicola is abundant in the soil ; 
and, however new the leguminous plant that is introduced, infection 
takes place unfailingly, and nodules appear. It is true that the erganism 
causing nodulation may not belong to the particular racial adaptation 
most suited to the host plant, and that in consequence an inoculation 
from a suitable pure culture might prove more effective. Again, it is 
possible that even a plant like clover, which would be infected at once 
through the previous growth of the crop, might be made a greater collector 
of nitrogen through the introduction of a race of bacteria which had 
acquired an increased virulence ; but in either of these cases the most 
that could’ be expected from the inoculation would he a gain of 10 per 
cent. or so in the crop. This great, though limited, measure of success 
depends upon two things—on obtaining races of 2. radicicola possessing 
greater virulence and greater nitrogen-fixing power than the normal race 
present in the soil, and again on the possibility of establishing this 
race upon the leguminous crop under ordinary field conditions, when the 
introduced organisms are subject to the competition both of kindred 
bacteria and of the enormous bacterial flora of any soil. Up to the 
present all evidence of greater nodule-forming power and increased 
virulence of the artificial cultures has been derived from experiments 
made under laboratory conditions without the concurrence of the mass 
of soil organisms. 
In the other case, however, where new land is being brought under 
cultivation and leguminous crops are being grown for the first time, 
there can be no doubt of the great value of inoculation with these pure 
cultures of the nitrogen-fixing organism. An example is afforded in 
Egypt, where land that is ‘salted,’ alkali or ‘brak’ soil, is being re- 
claimed by washing out the salt ; inoculation may be necessary before 
a leguminous crop can be started on such new land, though in many 
cases the Nile water used for irrigation is quite capable of effecting 
inoculation. The body of evidence brought together by the United States 
Department of Agriculture is very convincing, and shows in repeated 
examples that the use of Moore’s cultures has enabled farmers to obtain a 
growth of lucerne and kindred plants, which before had been impossible. 
In view of the economic importance the lucerne or alfalfa crop is 
assuming in all semi-arid climates, the financial benefit to the farming 
community is likely to be great and immediate. And since in the 
development of South African farming the lucerne crop is likely to 
become very prominent, both as the most trustworthy of all the fodder 
crops and as the one which brings about the maximum enrichment of 
the soil by its growth, the behaviour of the lucerne plant as regards 
