F. J. F. SHAW 



109 



deal of variation in this matter from one season to another. Both species rely 

 on the production of countless millions of minute seeds for their dissemination 

 and perenuation. These seeds are present all over the cultivated lands of 

 Bihar, their number and minute size being extremely favourable to their 

 dispersal in the strong winds which often prevail in February and March when 

 the fruits of Orobanche are ripe. 



The universal distribution of this parasite and the severity of the damage 

 caused to a valuable crop, such as tobacco, make any practical remedial 

 measures an important factor in Bihar agriculture. The field experiments 

 described in this paper were devised with a view to testing whether the claim, 

 which had recently been advanced, that ChiU saltpetre (sodium nitrate) was a 

 specific against '' tokras " was founded upon fact. 



11. FIELD EXPEEIMENTS. 



(1) PusA— Season 1914-15. 



A piece of land in the kitchen garden which had been under vegetables 

 (cabbage, cauliflower, potatoes) for some years, and was known to be badly 



N 



Sodiufn nitrate Wlhs. 



D 



Sodnari'mtt^ate 8 lbs. 

 Superphosphate 5 lbs 



Text-figure 1. 



