30 E. J. BUTLER. 
wilt, so that in neither of these cases was the danger of accidental 
infection considerable. 
Taking the whole of the experiments together, the conclusion 
is irresistible that Neocosmospora vasinfecta is a common soil 
saprophyte, which develops its perfect form on rotting roots of 
several (perhaps many) different plants and is wholly unconnected 
with the wilt diseases of the particular plants investigated so 
far in India. One might be tempted to go further and state that 
there is considerable doubt that the fungus is parasitic even in the 
United States. It seems at any rate clear that experiments intend- 
ed to demonstrate the parasitism of polymorphic species of Nectria 
or Neocosmospora are useless unless carried out with pure cultures 
derived unmistakably from the perfect form of the fungus, and so 
far as I know, this has not previously been done in the case of Neo- 
cosmospora. 
There are two questions which must now be answered. First, 
what evidence is there that the Indian Neocosmospora is identical 
with that of the United States, and second, if Neocosmospora is not 
the cause of wilt, what is the true cause ? In answer to the first 
I shall give a rather detailed account of the morphology and 
cultural characters of the Indian fungus which will leave no doubt 
as to its identity with that of the United States. 
The second question can as yet only be answered in one of the 
four wilts referred to above, that of pigeon-pea. The ground has, 
however, been cleared for the study of the cotton and gram wilts, 
and I hope that it will be possible to ascertain definitely the cause 
of these diseases. The indigo disease is likely to prove more diffi- 
cult, but a remarkable diminution im its intensity in the current 
season gives some ground for the hope that it may prove a passing 
outbreak of some half parasite, whose virulence may wane as the 
Java variety of plant gets acclimatised im its new home. 
The identity of the Indian and American Neocosmospora. 
Macroscopically and microscopically no difference can be 
detected between Neocosmospora vasinfecta from the United States 
