Worms That Commit Mass Suicide
An entire generation of worms commits suicide every year. Every individual casts off its own head.
These worms are a Himalayan variety of naids, fresh water animals vaguely related to earthworms. They are reddish-brown and seldom more than an inch long. The majority of the worms live with their heads buried in the mud, tail ends waving freely in the air. Upon any alarm their bodies contract leaving no signs of life.
Early in the Spring these worms literally lose these heads and die. Compared with those of most worms, their regenerative powers are quite feeble. It is believed that the decapitation is due to the fact that egg-laying is accompanied by such violent contractions of the body that the front segments are disconnected.
Every few years there is a report from somewhere in the United States or Europe of enormous numbers of dead earthworms covering the ground. A correspondent of the British scientific journal, Nature, reported in 1921: “About the middle of March I saw millions of dead worms morning after morning on pavements, roads and paths. They were great and small, young and old, of every known species and genus. They lay prone and even when they were able to reach a grass plot alive they lacked the power to burrow.” The phenomenon is unexplained. Examination of the dead worms shows no unusual parasite or evidence of disease.
Fish That Survive Freezing
There is a realm of “supercooled life.” Its denizens are deep water fish that live long and happily in temperatures below the freezing point of their blood. But whenever one of them comes in contact with even a single crystal of ice it freezes almost instantly. This strange phenomenon of marine life has been observed by biologists of the Woods Hole Oceanographic Institute.
These particular fish live at the bottom of Hebron fjord in northern Labrador. The temperature there is about 1.7 below zero centigrade. Some have been caught, brought to the surface, and then plunged into a bath of sea water cooled to exactly the same temperature. They survived for several hours. When, however, one of them came in contact with an ice crystal, it froze stiff in a few seconds. The explanation, it appears, is that these fish normally live below the depth at which it is possible for ice crystals to form in water.
Very careful experiments have shown that water can be carried far below its normal freezing point if it is kept entirely motionless and is absolutely free from minute particles of any sort which are necessary for the formation of ice crystals. This is about the condition that exists at the fjord bottom. Eventually, if the temperature is taken lower and lower, such water will solidify, but into a form far different from ice. It is noncrystalline and can best be compared with glass. But even if this happened in the Hebron fjord it would not necessarily bother the fish. Their blood presumably would turn to glass. There would be no breaking of body cells such as results from the swelling of ice crystals. After an indefinite period the animals might be brought out of the solid state, if the thawing could be accomplished quickly enough, none the worse for their experience. This has been accomplished with very minute organisms, but any techniques which might be used with higher plants or animals have not yet been discovered.
The extent of life in the supercooled world is unknown. It hardly can be confined to fish. All sorts of mollusks, echinoderms and worms also are bottom dwellers in Arctic and Antarctic waters. It’s not cold, but ice, that kills.