18 E. J. BUTLER. 
plants in the former were accompanied by seven deaths in the 
non-inoculated portion of the plot. No significance therefore 
attaches to them, except as showing that the infective material 
is not uncommon in local soils. In Series VIII there is good reason 
to suppose that the deaths were not due to wilt. 
On the other hand, in Series IX, where all the material used 
was rigidly sterilised, no deaths occurred, nor did any in Series VI 
(if we exclude the few plants killed by ants), though the seeds and 
pots were not sterilised and the plants were transplanted into open 
garden soil soon after moculation. In five out of the six pots inoc- 
ulated in Series V, no death occurred, nor did any deaths occur 
in Series X, in which pigeon-pea was inoculated with Neocosmo- 
spora from cotton, indigo and gram. 
Even though taken as negative evidence, the results so far 
given are sufficient to justify the conclusion that the Neocosmospora 
found on the roots of wilted pigeon-pea, cotton, indigo and gram 
plants in India is not the cause of the disease in the first of these 
crops ; the positive results obtained with another fungus detailed 
in Series XIV to XVII below leave no room for doubt on this point. 
Experiments with Neocosmospora vasinfecta Smith on Cotton, 
Indigo and Gram. 
The experiments with Neocosmospora on pigeon-pea must 
give rise to doubts regarding the generally believed parasitism of 
this fungus. The disease of this crop in India is a typical wilt, 
closely resembling those of cotton and other plants in the United 
States, where the cause is definitely stated to be this fungus, and of 
peas in Europe, where the same is suggested by the use of a name 
(Fusarium vasinfectum) given by Smith as a synonym for Neocos- 
mospora vasinfecta. It is unlikely that what is a virulent parasite 
on widely different hosts in other countries should be a harmless 
saprophyte on another host suffermg from a similar disease in India. 
The fact that, so far as published statements show, all successful 
inoculations obtained in other countries have been made with the 
