Plants That Kill
The lethal dose Socrates was condemned to swallow by the stuffed-shirtism of ancient Athens was d-propyl-piperidine. This is the deadly alkaloid in the spotted hemlock, a common European weed which now grows extensively over most of the eastern United States. A closely related European species is the cowbane which cows instinctively will not nibble.
The devastating illness which fell upon 10,000 Greeks of the Anabasis, Xenophon would have been interested to know, was caused by andromedotoxin. This is a resinous substance common to plants of the heath family the world over. It is the poisonous constituent of rhododendron, mountain laurel and some kinds of azalgias. Honey from the blossoms of plants containing it is extremely poisonous.
When pioneers first pushed their way over the Appalachians their settlements were ravaged by epidemics of a fatal disease—milk sickness. Farms and villages were abandoned as terror-stricken settlers fled from the scourge. It was due to tremetol, a complex chemical which has been found in several plants—chiefly white snakeroot which causes the disease east of the Mississippi. When cows eat the snakeroot the poison passes into the milk.
By far the most virulent plant growing in the United States is very little known although it has caused many fatalities. This is the water hemlock or cicula—very different from the spotted hemlock whose extract was forced upon Socrates. It grows in low, swampy places nearly everywhere. When the ground is soft in the spring its roots can be pulled easily from the soil and have a pleasant odor that attracts children. It causes heavy losses of livestock.
Next in virulence of all American plants is the whorled milkweed which contains a closely allied resinous material not yet satisfactorily analyzed. It has caused the death of countless cattle.
Caterpillars That Pretend to be Snakes
There are worm-snakes, snake-worms, and wormlike animals that instinctively imitate snakes. This is especially true of certain South American caterpillars—defenseless creatures whose only security is in mimicry.
A large, green tree-living caterpillar in British Guiana ordinarily remains motionless and looks like part of a vine stem. But when the branch is shaken it rears the front part of its body and stretches horizontally. At the same time it gives a twist expanding its front segment into a bulbous enlargement with a big menacing black eyespot surrounded by a yellow ring. This it remains for a few minutes, looking very much like a poisonous tree snake that lives among green leaves.
Serpent caterpillars abound in Brazil. The best example is Leucorhampha triptolemus, a creature that hangs vertically from stems of plants. When disturbed it twists and shows a front extremely resembling the head and back of a snake. The curve of the caterpillar is just like that of a serpent. It keeps up a swaying, side-to-side movement for several seconds. The whole effect is to change what seems an innocent plant stem suddenly into an open-mouthed snake with red jaws and ferocious eyes.