642 



Inoculation of Leguminous Plants. 



[FEB., 



Journal, see Vol. XL, page 348, September, 1904; page 669, 

 February, 1905 ; and page 725, March, 1905. 



The cultures from Munich were, on the whole, fresher than 

 those from Washington, which latter were, in some cases, received 

 as early as the autumn of 1904, though they could not be used 

 till the following spring. 



Dr. Hiltner prepares his cultures on petri dishes direct from 

 the healthy nodules of similar plants to those for which they 

 are designed. From these plates the tube cultures are made, 

 and the " virulence " of each culture is tested by the following 

 method : — Small pots are filled with a mixture of sand and peat, 



. - . _ , , ™_ „ , , , , , 



Fig. 1. — View of Dr. Hiltner's Experiment House. 



the latter in small quantities only ; the pots are then covered 

 with cotton-wool, sterilised in an autoclave, and cooled. Seeds 

 which have been germinated under sterile conditions are then 

 planted in the pots, and the inoculations made, three pots being 

 taken for each test. Only such cultures as produce abundant 

 healthy nodules on the roots of all the plants in the inoculated 

 pots are used for obtaining sub-cultures for distribution. 



It will be seen that though the proof of these cultures, and 

 the making of sub-cultures, takes some time, the cultures sent out 

 correspond as nearly as circumstances permit, to the natural state 

 in which they grew in the nodules. 



