426 
Journal of Agricultural Research 
Vol. XXVI. No. * 
lactic acid, glycerin, and water) to which a little eosin had been added. 
This type of preparation was employed because it was easier to handle, 
and it showed more clearly the location of the organism, its migration, 
and its action on the middle lamella than did paraffin sections. The 
latter were used in an additional series as a check upon the fresh prepara¬ 
tions and for the purpose of making photomicrographs. 
The developments in one of the two-day series are listed here in more 
or less detail. The examinations were made with the use of low power, 
high power, and oil immersion objectives together with a complete 
range of oculars. Polarized light was employed for examination of the 
walls, pectic granules, and crystals. The inoculations were made on 
March io, 1922, on tomato plants grown in the greenhouse. Since the 
morphology of the normal tomato stem is so well known, no description 
of it is given here. 
TWO-DAY-OLD INOCULATION 
Bacteria were noticed in considerable numbers along the path of the 
needle and inside of ruptured cells. Many of the intercellular spaces, 
especially those above and below the puncture, in the pith and in the 
cortex were found to contain the organism. The walls bordering such 
spaces were tinged with yellow, as is frequently the case with wounded 
tissue. When very dilute gentian violet was added, this yellow portion 
took up the stain more readily than did the other regions. This increased 
affinity of the walls for stains is probably the explanation of the difficulty 
found in demonstrating the bacteria with the conventional methods. The 
invading organism seemed to have some influence on the walls, which 
resulted in more or less swelling and loss of the property of double refrac¬ 
tion of light. Lateral migration of the organism for a short distance 
from the puncture had occurred in the subepidermal region (pi. T, A), 
where there are comparatively large and frequent intercellular spaces. 
It is noteworthy in this connection that the first layer of cells beneath 
the epidermis frequently contains anthocyan and has a higher sugar 
content than some of the other tissues. Whether or not this has an 
influence on the bacteria has not been determined. In this region also 
the phellogen has its origin. So it is not surprising that a stimulus to 
cell division in this portion of the stem should find a ready response. 
FOUR-DAY-OLD INOCULATION 
To the naked eye a slight swelling was evident about the puncture. 
Under the microscope this was much more apparent. The cortical 
cells had swollen and a few cell divisions had occurred. The old walls had 
increased in thickness while the yellow regions surrounding the position 
of the bacteria were extended. The organisms were easily located in 
some of the intercellular spaces and were traced a short distance into 
the middle lamellae between the adjacent cells. In the pith little change 
had taken place except a browning of certain of the intercellular spaces 
about the bacteria and occasional divisions. It was noticed again that 
the walls bordering the bacteria took the stain more heavily. With 
polarized light it was again observed that the yellowed walls near the 
organisms were not doubly refractive. No real difficulty was experienced 
in differentiating the bacteria from the pectic granules in the middle 
lamella or from crystals. In cases of doubt the former were dissolved in 
