mTELLÎGENCE OF SQUIERELS. 181 



me to the most interesting, and, at the same time, the most difficult series of inquiries 

 connected with the whole subject, viz., "What, upon analysis, is this feigning in animals? 

 In how far is it instinctive, and in how far an intelligent and deliberate adaptation of 

 means to an end under unusual circumstances ? How did the instinct of feigning death 

 and injury arise in the first instance ? Has feigning been confounded with something 

 else totally different, such as the results of fear, surprise, etc. ? Is the expression, " feigning 

 death," not misleading in itself? The matter is so intricate, and such diverse views have 

 been entertained in regard to the subject of feigning, that it will be necessary, in order to 

 arrive at a solution, to examine critically several of the views advanced. 



Feigning death has been observed in many different genera of insects, in snakes, 

 fishes, numerous birds, crustaceans, and several mammals. 



In a most interesting account of experiments on certain animals, by Prof. Czermak, 

 published in the Popular Science Montldy (Vols. Ill and IV), it was shewn that in the 

 crayfish, in hens, geese, ducks, turkeys, pigeons, the swan, etc., a state, which this writer 

 recognised as having a physiological basis, but which he did not attempt himself to 

 explain, occurs. In all these animals, under the influence of steady restraint of motion, 

 or, combined with that, i:)rolonged gazing at some object held just before the eyes, a 

 condition of quietude and partial or complete unconsciousness was induced for a shorter 

 or longer period, after which they regained their usual condition. In some of the animals 

 the muscles became rigid, i. e., the cataleptic condition was induced. 



About five years later. Prof. Preyer gave the subject a thorough experimental examina- 

 tion. The starting point of all these experiments was the experimenlum mirabile of Kircher, 

 in 1646 ; Preyer seems to use the term " cataplexy " to cover what is now more commonly 

 called "catalepsy," or "hypnotism." Preyer believed that the shamming death of certain 

 species of the Articulata, when threatened by danger, was due to cataplexy. The condi- 

 tion was attended in certain animals by stupor, violent tremblings of the extremities, and 

 other pronounced disturbances of function and psychic state. This writer then explained 

 the condition, called by some "shamming death", by a sudden, powerful, unexpected and 

 unusual stimulus acting on the centripetal nerves, producing an emotion of fear which 

 acts on the will, inhibiting it and producing stupor ; " deathly terror," in a word, is the 

 condition, and not feigning, according to Preyer. 



The well-known physiologist, Heideuhain, performed many experiments, chiefly on 

 the human subject, with a view of arriving at a physiological solution of these remark- 

 able phenomena. He has framed the theory, that hypnotism is due to the inhibition of 

 the cortical cells of the cerebrum, caused by the gentle prolonged stimulation of the nerves 

 of the face, eyes or ears. 



Dr. Clarke, in the Popular Science Monthly (Vol. IX), discusses the results of Czermak 

 and others, and concludes that " they depend wholly and only on fear," for he maintains 

 that the experiments succeed best in the wilder individuals of the species. But Dr. Clarke 

 is scarcely consistent, for he points out in the same paper that animals cease to struggle 

 because they find it useless, and this he ascribes to intelligence. 



Dr. D. W. Prentiss, in the American Naturalist (Vol. XVI), examines the matter from the 

 physician's point of view. After referring to the " dancing," " convulsive " and " laughing " 

 manias, and to certain phenomena in animals like those already described, he concludes 

 that the factors entering into the phenomena of Czermak and others are fear, 



