Dec. i t 1923 
Morphology of Crowngall 
43 i 
were noticed on some of the main stems at the points of inoculation. In 
about 12 days the first signs of “secondary tumors” began to appear. 
After about four weeks it was noted that only about 5 per cent of the 
stems showed any “secondary tumors” at all, and of this number great 
variation in the infection was manifest. This may be seen in Flate 3, 
which shows the galls about seven weeks after inoculation. In each case 
the needle passed through the leaves marked a and struck the stem proper 
at b, where the “primary gall” developed. “Secondary galls” appeared 
at intervals above and below. It is to be noted that the stems A and E 
received such a heavy inoculation that the bud was unable to expand, and 
consequently we have the stem ending in a mass of gall tissue. C and D 
were less completely involved and were able to expand to a certain extent. 
In each case three nodes developed galls above the point where the needle 
struck the stem. In the case of B the stem was still less involved, so that 
“secondary galls” appeared only along the intemodes above and below 
the point where the stem was inoculated. Here there is some prevention 
of expansion, but it is not nearly so great as in any of the other cases. 
Serial sections were cut through the “secondary galls ” marked c and d. 
Plate 4, A, shows a section cut between b and c. The positions are 
marked e where the walls were stained more heavily as a result of the 
presence of the bacteria. In the center at st a small amount of prolifera¬ 
tion appears. Here we have the early stages of “tumor strand” forma¬ 
tion. Figure B shows in section the gall c of Plate 3, B. The position 
marked X on the section was directly above the strands. So far, in this 
gall there has been no differentiation into vascular tissue. Plate 4, C, 
shows the “tumor strand” as it proceeds on to the next gall. There was 
no connection in all its course between this “strand” and the vascular 
tissue. The “strand” opens out into the gall marked d of Plate 3, B. 
Thus we find interesting developments similar to those that Smith (5, 
p. 236) has described in the daisy. Plate 4, D, shows a section of this gall. 
It seemed that a stimulus similar to that which operated in the tomato 
stem (/>. 4.28 s ) to produce vascular tissue out of tumor cells had acted here. 
This development appeared to start in one place and to spread in such 
a way as to produce a more or less spherical mass of woody tissue. No 
evidence was found to indicate that there was any connection between 
the type of tissue inoculated and the type of tissue produced by the 
“ secondary tumor.” This does not seem to conform to Smith’s statement 
(5, p. 243) that, “ . . . the structure of the secondary tumor repeats that 
of the primary tumor . . . .” If such were the case one would expect 
that two galls resulting from the same “tumor strand” as c and d of 
Plate 3, B, would have the same structure. But we have seen that one 
is vascular in a large degree, while the other is entirely parenchymatous. 
Smith employs the point given above as an argument for the invasive 
character of the “tumor strand” and “secondary gall” (5, p. 243 ), but he 
does not apply it without qualification, either to teratomatous tissue 
(5, p. 247) or to woody tissue (5, p. 248). 
Results similar to those obtained in experiments on the sweet pea have 
also been secured on the sunflower. During the last week in July, 1922, 
150 inoculations were made on sunflowers grown in the experimental gar¬ 
den at Madison, Wis. At the time of inoculation the plants stood about 
2 feet high. In each case only one puncture was made on a plant, and 
that passed through the rapidly elongating region of the condensed bud. 
The plants were harvested on October 12, 1922. At this time they stood 
8 to 11 feet high and bore large heads from which the seeds were 
