428 
Journal of Agricultural Research 
Vol. XXVI, No. 9 
bacteria were again observed in the yellowed intercellular spaces and in 
no other position. One could trace their course through the tissue by 
the changes they produced in the properties of the adjacent walls. No 
evidence was found to indicate that the bacteria were inside of any of the 
living cells. 
TEN-DAY-OLD INOCULATION 
A general increase was noted of all the tissues previously mentioned. 
The affected tissue of the tomato had become so distorted that the inter¬ 
cellular spaces which were filled with gas showed a disorderly and bizarre 
arrangement. Calcium oxalate crystals were observed in unusual 
quantities in some of the larger cells. A certain amount of distortion 
among the large cells indicated that pressure was being exerted by the 
gall tissues. Up to this time the xylem showed no material increase in 
thickness. The bacteria were found as usual in the intercellular spaces 
in association with some of the yellowed walls. 
TWELVE-DAY-OLD INOCULATION 
There was a continued enlargement of the gall area and the individual 
tissues of the tumor. The xylem and phloem bordering the gall tissue 
showed an increased width. This was possibly due to an unusual amount 
of catnbial activity under the influence of the stimulus provided by the 
bacteria. By this time the hyperplastic regions had encroached upon 
the hypertrophic areas to such an extent that the earlier structure of a 
collection of cylindrical gall tissue about invaded intercellular spaces 
was partly obscured. 
FOURTELN-DAY-OLD inoculation 
No new structures were noticed, but a further enlargement had taken 
place in all parts. By this time the gall had developed the regions 
of thin-walled rapidly dividing cells intermingled with those of large 
hypertrophic cells which are characteristic of old galls. The former 
appeared to contain no air spaces, while the latter had large irregular ones. 
The bacteria were still to be found in some of the yellow walled inter¬ 
cellular pockets. These were more widely scattered than they were in 
the younger galls and appeared not to contain so many bacteria. 
sixteen-day-old inoculation 
Growth had continued in all parts. For the first time, some of the 
gall tissue which originated in the subepidermal region showed differen¬ 
tiation into vascular elements. There was no connection between this 
tissue and any of the tissue produced by the cambium, so the tracheids 
must have been produced by tumor cells which in turn came from cortical 
cells. Smith (5, p. 248) has reported similar findings. The groups of 
calcium oxalate crystals were increasingly numerous. 
eighteen-day-old inoculation 
Vascular tissue was noted in larger quantities in the portion of the 
gall derived from the cortex. It was found to appear also in gall tissue 
which originated in the pith. The bacteria, although still present in 
