HOW MUCH ANIMALS KNOW. 39 



we take against such evasive foes working as we do in the dark bo- 

 using antiseptics, are evidently insufficient. A substance that kills 

 one bacterium may not hinder the development of its neighbor, and 

 our employment of antiseptics is always dependent upon their specific 

 action. There exists no universal remedy against microbes. Science 

 alone can teach us how to contend against them. Translated for the 

 Popular Science Monthly from the Revue Scientifiaue. 



HOW MUCH ANIMALS KNOW. 



By F. A. FEENALD. 



~\TO phenomena in nature are watched with more interest by all 

 -i-N classes, young and old, ignorant and educated, than the displays 

 of intelligence in the inferior animals. From the dog, which occupies 

 a position of intelligent companionship with man, down through the 

 less favored species even to the lowest groups of animal life, we see 

 manifested all degrees of that wonderful attribute which in its highest 

 perfection constitutes the human mind. It is not surprising that these 

 various indications of something like a capacity for thought should be 

 of universal interest, but it also has a deeper meaning, which it is the 

 office of science and philosophy to explore, and which relates to the 

 profound and mysterious problem of " mind in nature." Before phi- 

 losophy can make much headway with this question, however, there 

 must be a more critical scrutiny of the question as to what degrees of 

 intelligence different grades of animals really possess. Dr. George J. 

 Romanes, in his recent interesting book on "Animal Intelligence," 

 engages with this subject as a scientific question of comparative psy- 

 chology, and he has done a good deal toward winnowing away the 

 fictions that have become current in relation to the mental manifesta- 

 tions of the lower tribes, and has given us probably the most trust- 

 worthy book extant upon the subject. We cull from his pages a series 

 of representative instances of animal sagacity which the reader will 

 find both entertaining and instructive. 



It is common to quote the oyster as the lowest example of stupidity, 

 or absence of anything mental, and, as it is a headless creature, the 

 accusation might not seem wholly unfounded. Yet the oyster is not 

 such a fool but that it can learn by experience, for Dicquemase asserts 

 that, if it be taken from a depth never uncovered by the sea, it opens 

 its shell, loses the water within, and perishes. But oysters taken from 

 the same depth, if kept in reservoirs where they are occasionally left 

 uncovered for a short time, learn to keep their shells closed, and then 

 live for a much longer time when taken out of the water. 



This fact is also stated by Bingley, and is now turned to practical 



