350 Experiments in Soil Inoculation. [sept., 



Failure of the nitragin to effect an improvement in the crop 

 when it was sprinkled on the seed is now believed to be due to 

 the action of secretions produced by the seed in the early stages 

 of germination. These secretions are found to be rich in salts 

 of potash, and when brought into contact with the bacteria in 

 question they induce changes allied to plasmolysis, and these 

 changes are subsequently followed by death. This difficulty was 

 found to be got over by moistening the seed and allowing it to 

 sprout before the nitragin was applied ; but manifestly such a 

 procedure would always be difficult, and often impossible, to 

 carry out in practice. The object, however, would appear to have 

 been gained in another way, namely, by cultivating the bacteria 

 in a medium that imparts to them the necessary power of 

 resistance. Such nourishment may take various forms, but that 

 which gave the best results consisted of a mixture of skim milk, 

 grape sugar, and pepton, and it is in this medium that the 

 organisms of the nitragin now distributed are cultivated. 



During the past year more than 400 experiments were carried 

 out in different parts of Germany with pure cultures prepared 

 at the Agricultural Institute at Munich ; 98 of them were 

 carried out in Bavaria, and from a recent report by Dr. Hiltner* 

 it appears that the results were, on the whole, exceedingly 

 favourable ; of the whole number in only nine cases was the 

 inoculation without result, though in eight others it is described 

 as indecishe. The number and result of experiments with each 

 kind of plant were as follows : — 





No. of 

 Experiments. 



Favourable. 



Without 

 Result. 



Undecided. 



Serradella 



23 



21 



1 



1 



Yellow lupins ... 



23 



20 



2 





Mixed leguminous plants 



15 



14 





I 



Vetches ... 



1 3 



11 



1 



1 



Blue lupins 



5 



3 





2 



Peas 



5 



3 



2 





Red clover 



4 



1 



I 



2 



Trifolium incarnatum ... 



2 



2 







Lucerrte ... 



2 



I 



I 





Horse beans 



3 



2 



I 





Other leguminous plants 



3 



3 









98 



81 



9 , 



8 



* Naiurwissensckaftlicke Zeitschrift fur La/uf-und Forstwirtschaft : , March, 1904. 



