434 
Journal of Agricultural Research 
Vol. XXVI, No. 9 
these plants may be seen in Plate 6, E and F. Cross sections through 
the Paris daisy showed intercellular spaces seventeen intemodes above 
the point punctured in the leaf primordia and fifteen internodes in the 
pith. In the sweet pea intercellular spaces were found in the pith seven 
intemodes above the point of puncture. 
SUMMARY 
1. The crowngall bacteria have been observed consistently in an inter¬ 
cellular position in five series of inoculations on tomato stems which 
were examined at two-day intervals until the galls showed mature char¬ 
acters, that is, distinct regions of hyperplasia, hypertrophy, and vascular 
elements. 
2. The bacteria were found to be associated with a change in neigh¬ 
boring cell walls which was manifested by a change in color, in staining 
reactions, and in the power of double refraction of light. 
3. The bacterial stimulus appears to attract the dividing nuclei to the 
adjacent part of the cell and thus to disturb the polarity of the cell. 
4. The walls resulting from the early divisions were laid down in the 
portion of the mother cell near the intercellular space containing the 
bacteria. 
5. The divisions of the cells in the early stages of gall formation were 
observed to form a more or less distinct sheath about the position of the 
bacteria. 
6. The manner of cell division in the early stages indicated the source 
of the stimulus and the position of the bacteria. In older galls this rela¬ 
tion was not so clear. 
7. The younger galls appeared to be composed of groups of sheaths 
or strands of tumor tissue surrounding invaded intercellular spaces. 
* 8. Calcium oxalate was found deposited in much larger quantities in 
gall tissue than in normal tissue. 
9. “Tumor strands’' and “secondary tumors” have been secured only 
when the inoculation puncture was made in the region of elongation close 
behind the condensed buds of such plants as sunflower, sweet pea, and 
tobacco. They were secured in only about 5 per cent of the inoculations. 
10. Intercellular spaces have been found in the condensed buds of 
sunflower to extend from the usual position of puncture up past fifteen 
nodes. The internodes in these buds were observed to be very greatly 
condensed. A similar situation has been found in sweet pea, tobacco, 
and Paris daisy. So in all these plants, it appears that the liquid re¬ 
leased by a puncture might flood the intercellular spaces for a number 
of internodes, and the bacteria, migrating through the liquid might 
involve the same amount of tissue. 
11. The elongation of the internodes in the condensed tfud above the 
puncture was found to be of very great importance in the separation of 
the “secondary galls” from the point of puncture. 
12. A heavy inoculation of the growing region prevented the expansion 
of the intemodes. 
13. No evidence has been found to show that “secondary tumors” 
and “tumor strands” invade the normal tissues. They appear to be 
part of the “primary gall” which was carried up by elongation of the 
invaded region. 
14. The specialized tumor tissue found in “secondary galls” appeared 
to develop independent of any relation to the “primary galls.” 
