12 
denser structure, and the self-evident corollary is that methods and fer- 
tilizers promoting a rapid succulent growth should be avoided in all 
locations infected with the root-knot. 
EFFECTS OF THE INVASION OF THE ANGUILLULA. 
I have found mature worms, males and non-pregnant females, in root- 
lets but a few days old, and under circumstances which involved the 
necessity of invasion from without the root. See Experiment No. 22. 
These Anguillul® were small enough to enter the “ stomata” of epi- 
dermal tissues, active and strong enough to even penetrate cell- walls, or 
to separate cells in loosely connected tissues. Once within, they could 
easily pass through the Cienchymatous system of the Parenchyma to 
any portion of the root, and I think it not unreasonable to infer that in 
this manner they obtain entrance in young rootlets. 
Their presence causes a rapid proliferation of cells, resulting in a soft, 
unnatural, irregular growth of the root, with low vitality, and a varied 
effect upon the plant or tree. 
The Chenopodium, Eupatorium, Artemisia, Amarantus, Gossypium, 
Solanum, and Petunia have the enlargements usually on the sides of 
the main stem, near the surface. The “ tap-root,” descending deeply is 
rarely affected, and the plants seem slightly affected till the sub-corti- 
cal layer is filled with worms in all stages of growth. This checks 
growth, either by their absorption of the nutrition gathered by the root- 
lets, or obstruction of the Cienchymatous ducts, the food supply is cut 
off before decay is visible, the leaves wither, the stems shrivel, the plant 
dies. (Plate VIII, 1 u, 4 b.) 
The roots of the Okra, Radish, Turnip, Cabbage, Cucumber, Melon, 
Cow-pea, Peanut, Tomato, and Egg Plant enlarge enormously, soon be- 
coming little else than masses of decaying tissues. The plant stops 
growth, the fruit either becomes distorted or drops prematurely, the 
leaves change color and fall off, and the plants die so rapidly as to justify 
the usual expression ‘‘struck by lightning,” applied to the fields of 
Melons, Cucumbers, Tomatoes, and Cow-peas so often badly affected 
by the root-knot. (Plates I, II, III, 1Y, and VIII.) 
In nurseries of young fruit-trees the greatest mischief occurs. The 
soil is usually carefully prepared by heavy fertilizing and culture, and 
the seeds of the Peach, Orange, and English Walnut are sown for 
stocks. When the tender shoots first appear many wither and die at 
once, others grow vigorously till the end of the first season, when they 
are usually budded with known and valuable varieties of fruit. The 
next spring these buds put out tardily and make a weak growth, the 
leaves become spotted or yellow, then drop, the bud dies, feeble strag- 
gling shoots sprout around the stem, which maintain a sickly vitality 
till the first drought, when the tree dies, and an examination dis- 
closes the cause in the knotty, decaying roots, without rootlets or 
fibrill®. 
