On Purples or Ear-Cockle in Wheat. 
351 
receives confirmation from the observations and experiments of 
Davainc. He made many attempts to produce the disease in 
healthy plants, but he found he could not succeed unless he 
applied the vibrios at a very early stage of the development of 
the flower, when it was yet only a few millimetres long, and before 
the scales or paleoles, stamens and pistil, are distinct from each 
other. As soon as the plant had reached that stage in develop- 
ment, in which the stamens appear and the pistil can be distin- 
guished, it was proof against the attack. 
The growth of the gall is, as I have said, much more rapid 
than the growth of the natural flower. In the earlier stages of 
the gall the nature of the organs which the worm has attacked 
can be more clearly determined. The margin of the leaf can 
be traced terminating in the somewhat indurated apex, and 
the hairs more closely correspond with the hairs on the properly- 
formed scales. 
Fig. 4. — Young Galls, external aspect and section, sJiowing in each Cell 
on& or two Parent-icornis and a great mass of Eggs. 
When the galls in this early stage are cut and examined 
(Fig. 4), they are found to contain one or more parent worms 
with numerous eggs. The eggs may be observed in all stages 
of advancement (Fig. 5). 
Fig. 5. — Adult Female Vibrio (Tylenchus tritici, Bastian), with Eggs, 
from some of which the young Worms are escaping. 
