HAVE FISHP^S MEMORY. 383 



duced in fish whose labyrinth had been removed. Many of the accounts 

 sent to me mention the fact that fishes in a lake are disturbed when- 

 ever a cannon shot is fired on shore. In his book on animal life in the 

 Austro-Hung-arian plain, Aug. Wojsisovics von Wojsvar tells, as I see 

 in the '■'' Ppomethem^\ that the Servians thrust the hucskalo, a wooden 

 instrument, into the water with an abrupt motion, in order to attract 

 the sheath-fish [Snurus glanis\. But possibly the strong undulation 

 gathering- force in the water, rather than the sound, informs the fish 

 of the moving of a heavy body at a distance. 



From the data at our disposal we must infer that fishes are aware of 

 violent percussions, such, too, as are caused by sound waves, but it is 

 most doubtful whether the}^ receive impressions of sound as we ordi- 

 narily use the word. 



In the skin covering the head of fishes are situated numerous delicate 

 sense organs, and similar ones are arranged in a line extending from 

 the head to the tail on the side of every fish. This lateral line can 

 always be recognized in the scaly animal. Issuing from the brain 

 close to the nerve of equilibrium a vigorous nerve supplies the entire 

 apparatus. Manifold observations in the past seemed to indicate that 

 this apparatus was sensitive to variations of pressure exerted by the 

 water, and that therefore it is well fitted to enable the animal to adjust 

 itself to its fluid medium. Moreover, the same lateral line occurs in 

 amphil^ians living in the water, and disappears in such, like frogs and 

 salamanders, as remain on land in a second period of their life. Fish 

 whose sight has been removed continue to avoid obstacles fairly well, 

 and they are aware of the unobtrusive glass covering of the aquarium 

 walls unless some special impulse sends them darting wildly hither and 

 thither. Stahr tells of the male of a Chinese pet fish, that, when court- 

 ing, arrayed in all the glory of his wedding finery, he is in the habit 

 of rushing toward the female with great vehemence, and then sud- 

 denly subsiding, his breast fins spread out wide, without so much as 

 touching his mate. The behavior of the female shows that somehow 

 she is aware of these repeated concussions communicated to her only 

 by the water. In agreement with older authors, Stahr supposes that 

 the knowledge reaches her by means of the apparatuses situated in the 

 lateral line. In fact, on their removal (Richard), the injured animal 

 conq^letely loses its balance, and Bonnier has proved conclusivelv that 

 fish so treated lack the ability to maintain their equipoise against the 

 various disturbances of the water. From fish whose lateral line had 

 been destroyed with a hot platinum wire, he also took other sense 

 organs, the eyes, the ears, in various combinations. It appeared that 

 the labyrinth and the lateral line alike serve to receive shocks and 

 difl'erences of pressure, but that the special function of the lateral line 

 is to receive the unpression of the direction of a shock. Fuchs suc- 

 ceeded in proving in individuals with unimpaired sense organs that the 



