PHYTOLOGY AND THERAPEUTICS. 101 
gave a magnification of 850 diameters. Drawings representing cross-sections of 
the tubercles at this power were obtained with the aid of an improved Abbe 
camera. Specimens representing a portion of a cross-section of tubercles taken 
from plants seventy-two and ninety-nine days old are shown in figs. 4 and 5, re- 
spectively. 
EXPLANATION OF Mycrettum.—It should be noted that the mycelium that 
appears to run from cell to cell is a bacterial product and is therefore not a true 
mycelium. The apparent mycelium is what is known as a bacterioid condition ; 
the bacteria become distributed throughout the cells and finally die. It is in 
this dead or decayed condition that the bacteria become available as plant food. 
The mycelium, or bacterioid condition, is the transition stage from the individual 
bacteria until their absorption by the plant. The change of the bacteria into 
the bacterioid condition is shown at d, fig. 5. 
EXxpLaNaTion oF Microscopic Drawina.—Fig. 4 shows the cells, a; the 
nuclei, 0; and the infecting mycelium (bacterioid condition), c. It will be no- 
ticed that the mycelium is formed through the cell-wall, appears to send off 
branches, and has a special liking for the cell nuclei. In the lower portion of 
Fia. 4. Fig. 5. 
Cross-section of soy-bean Cross-section of soy-bean 
root tubercle, , root tubercle. 
fig. 4 is shown the mycelium branching to two nuclei, one of which seems to lie 
below the other and many belong to a lower layer of cells. Fig. 5 shows a cross- 
section at a little later stage of development. Asin the former case, it shows the 
mycelium, ¢, butina little different form. Inone instance the mycelium seems to 
envelop the inner wall of nearly all of one cell, and a portion extends through the cell 
wall into the adjoining cell. In addition to this, there is shown at d a cluster of 
small dots, which are probably individual bacteria. Also at e are found peculiar 
dark bodies, some of which are imbedded within the cell wall, while others are 
isolated or connected with threads, or hyphx. The latter bodies may possibly be 
bacteria, but it seems to be more probable that they are something else. They 
may. be due to some foreign substance that has the power of absorbing the stain 
to a greater degree than the surrounding tissues. 
EXTENT OF SOY-BEAN MICRO-ORGANISM IN THE UNITED STATES. 
After the success of inoculating the beans with imported soil was assured, it 
was thought to be an interesting point to ascertain how far these particular 
micro-organisms had spread in this country. Accerdingly inquiries were sent to 
