ROOT-NODULES OF LEGUMINOSAE. E2E 
Successful results with serradella were obtained by Luberg on dry sandy land from seed-inocu- 
lation which was followed by unfavorable weather. This was probably due to the fact that serradella 
seeds are protected by a very heavy seed-coat and hence do not need the protective substance fatal 
to bacteria. 
Inoculation by strewing infected soil seems relatively a better method than seed inoculation, 
yet it needs improvement. Only when the soil offers to the bacteria favorable conditions for growth, 
or when its bacterial content does not act unfavorably on them, as for example on moors and marshes, 
can inoculation with soil either before or after sowing be used with any certainty of success. 
Tacke obtained remarkable results with peas on newly-cultivated moor-land. The crops resulting 
from seed-inoculation were 282 per cent greater, from soil-inoculation 384 per cent larger than crops 
from uninoculated land or seeds. Von Feilitzen obtained like results in Sweden on similar new land. 
His seed-inoculations gave an increase of 55 per cent straw and 116 per cent seed. This author also 
found an advantage in the use of nitragin over that of natural earth inoculation, as the latter caused 
a heavy growth of weeds fatal to the crop. 
Wollney concludes from his experiments with peas, field beans, white lupins, scarlet clover, and 
serradella, that nitragin can be successfully used only on newly cultivated soils or on soils which 
have borne no legumes and are sandy without humus. On soils containing humus, virulent root- 
nodule bacteria are already present and inoculations are useless. He bases this opinion on the fact 
that nodules occurred on the roots of all the plants sowed, yet only the peas showed increased growth. 
In all these cases, according to Hiltner, results would probably have been favorable if inoculations 
had been made with organisms more virulent than those present in the soil. 
Schulze on the other hand, like Kiihn, expresses a belief in the future of nitragin. He claims 
that the few cases which have been successful prove that nitragin can work, and that what is now 
needed is elimination of unfavorable factors and improvement in the methods of application. 
The excessive claims made for the earlier nitragin against which, however, Nebbe and Hiltner 
protested repeatedly but in vain, have undoubtedly had much to do with bringing inoculations into 
disrepute. Hiltner thinks, however, that pure culture inoculations will in the future, in spite of all 
obstacles, win a place in practical agriculture, and he has desired especially because of his connection 
with the old nitragin to help on in all possible ways this view which he has never ceased to maintain. 
From 1900 on, only pure cultures were used by Hiltner. 
Although a former experiment by Loges gives favorable results from soaking the seeds before 
inoculation, numerous experiments by Hiltner have shown that this method is not to be generally 
recommended, since seeds so treated, although germinating readily, are especially liable to rot in 
the soil.* ‘Thiele failed to get a stand with either peas or beans which had been soaked 24 hours 
before sowing since all the beans and most of the peas rotted in the ground. He attributed this to 
dry weather prevailing before and after sowing. Hiltner, however, thinks the failure due to the 
destructive action of soil organisms. 
Dr. Boéhme, on the other hand, obtained strikingly favorable results with yellow clover by 
soaking the seeds in a quantity of water containing the bacteria into which was sifted a little fine 
earth, and sowing after two days when they had absorbed all the water and were dried out. -The 
inoculated plants attained a height of 160 mm. with deep green leaves 15 mm. broad, while the 
uninoculated plants were only a few centimeters high with pale green leaves scarcely 4 mm. broad. 
In 1901, 59 experiments were carried on for Hiltner by 31 different men according to the following 
directions: Soaking seed previous to sowing must be avoided; the seeds should be thoroughly wetted 
with the inoculating fluid, the excess of moisture removed by a sprinkling of dry sand, after which 
the seed drill can be used for sowing. As at this time the injurious action of the substance contained 
in the seed-coat had not been discovered, this factor could not be taken into account. Hence in none 
of the experiments of 1901 was the method used which is now considered necessary. Yet the collec- 
tive results of the year’s work justified great hopes for the future. 
One group of 13 experiments was eliminated by the fact that dry weather prevented germination 
or destroyed the young plants. In another group of 21 experiments the effects of inoculation were 
either imperceptible or doubtful. For example, in one experiment with beans, Braun states that 6 
weeks of drought caused the plants to wither before they had bloomed. At the beginning of August, 
after a good rain, growth again set in and the crop reached maturity, but no effect of the nitragin 
was observable either in foliage or fruit. In another case while inoculated serradella gave 13 per cent 
increase in dry substance, inoculated red clover showed an equivalent loss. Concerning these results, 
Hiltner says: 
“We also are of the opinion that results can not be obtained under all circumstances by inocu- 
lation; but for the present we cling fast to the hope that in the future, after further improvement of 
*Consult Hiltner’s paper. Arb. a.d. Bio. Abt. f. Land. u. Forst. a. k. Ges., 11 Bd., Heft. 1, Berlin, 1902. 
