36 KH. J. BUTLER. 
rapidly dropped into a tube of sterile prepared medium. In this man- 
ner it was hoped to destroy all but organisms deep in the tissues. 
All the roots thus treated gave rise to the growth of a bacillus which 
gave characteristic colonies on nutrient agar. In some the fungus 
known to be present within the root was killed by the treat- 
ment, and no mycelial growth occurred. In others a filamentous 
fungus appeared on the surface or at the cut ends, and was easily 
got into pure culture free from the bacillus. Only these two organ- 
isms, a bacillus and a fungus, were thus obtained and work was 
continued with them. 
Series XIV. 
The culture was obtained from a wilted pigeon-pea root grown 
in soil which in part originated from pot V of Series V above (p. 10). 
On August 21st, 1907, all the plants in this pot had wilted and were 
pulled out. The soil was then mixed with some fresh potting earth 
in equal parts, and filled into two pots. In these pigeon-pea and 
indigo respectively were sown. Wilt appeared in the former on 
October 10th, and all the plants were dead by November 21st. They 
were pulled out and perithecia of Neocosmospora developed on some 
of them after 10 days in a moist chamber. Pigeon-pea was resown 
in the pot immediately. On November 25th, the indigo plants 
in the other pot (still perfectly healthy) were pulled out and pigeon- 
pea sown in the pot, after adding as usual an equal bulk of fresh 
potting soil. The pigeon-pea after pigeon-pea developed wilt 
durmg January, 1908, and that after indigo at the end of the same 
month. Eight plants in each pot were dead by March 28th. The 
rest were then pulled out and the soil from the two pots mixed, part 
being used to grow yet another pot of pigeon-pea. This showed 
wilt in a month, being the fourth generation of seedlings that had 
succumbed to the infective material of pot V. 
On May 19th, 1908, a very recently infected root was selected 
from a wilted plant of the last batch, washed in water and alcohol 
and flamed as described above, and dropped into a tube of nutrient 
agar. On the 2nd day the contents of the tube, now clearly show- 
ing a growth of hyphe and bacteria around the root, were plated 
