It will take the human race many, many years to unlearn, and to recover from the effects of the superstitious cult of the shaman, who exists, not only among savages, but also in the most highly civilized races of the world! Superstition is the antithesis of knowledge; in fact, it is but another name for ignorance. There is yet another exceedingly interesting psychical trait to be noticed in the lower animals, especially in insects; I refer to the instinctive habit, letisimulation (_letum_, death, and _simulare_, to feign). The word "instinctive" must not be used, however, when this stratagem is to be observed in the higher animals other than the opossum; for many of these animals sometimes make an occasional and a _rational_ use of it, as I will endeavor to show in the next chapter. CHAPTER IX LETISIMULATION The feigning of death by certain animals for the purpose of deceiving their enemies, and thus securing immunity, is one of the greatest of the many evidences of intelligent action on their part.[108] Letisimulation (from _letum_, death, and _simulare_, to feign) is not confined to any particular family, order, or species of animals, but exists in many, from the very lowest to the highest. The habit of feigning death has introduced a figure of speech in the English language, and has done much to magnify and perpetuate the fame of the only marsupial found outside of Australasia and the Malayan Archipelago. "Playing 'possum" is now a synonym for certain kinds of deception. Man himself has known this to be an efficacious stratagem on many occasions. I have only to recall the numerous instances related by hunters who have feigned death, and have then been abandoned by the animals attacking them. I have seen this habit in some of the lowest animals known to science. Some time ago, while examining the inhabitants of a drop of pond water under a high-power lens, I noticed several rhizopods busily feeding on the minute buds of an alga. These rhizopods suddenly drew in their hair-like cilia and sank to the bottom, to all appearances dead. I soon discovered the cause in the presence of a water-louse, an animal which feeds on these animalcules. It likewise sank to the bottom, and, after examining the rhizopods, swam away, evidently regarding them as dead and unfit for food. The rhizopods remained quiet for several seconds, and then swam to the alga and resumed feeding. This was not an accidental occurrence, for several times since I have been fortunate enough to witness the same wonderful performance. There were other minute animals swimming in the drop of water, but the rhizopods fed on unconcernedly until the shark of this microscopic sea appeared. They then recognized their danger at once, and used the only means in their power to escape. Through the agency of what sense did these little creatures discover the approach of their enemies? Is it possible that they and other like microscopic