FUNCTION OF LATERAL-LINE ORGANS IN FISHES. L89 



the nerve of only one side was cut, a slight luck of orientation and of muscle coordi- 

 nation could sometimes be observed. These seem to be the only noteworthy 

 experiments on the lateral-line organs that were carried out before the time of 

 Fuchs's work. 



Fuchs (1894, p. 467) experimented chiefly on the torpedo, a fi>h which possesses, 

 in addition to the lateral-line organs proper, the vesicles of Savi and the ampullae of 

 Lorenzini. Fuchs cut the nerves connected with these two special sets of organs, 

 hut without being able to detect any significant chance in the subsequent movements 

 of the fish. He then exposed the nerve supplying the vesicles of Savi, and. having 

 placed it in connection with an appropriate electrical apparatus, he found that by 

 pressing lightly on the vesicles a reduction in the current from the nerve could he 

 demonstrated. As this reduction is believed to indicate the transmitting activity of 

 nerves, it follows that the pressure applied to the vesicles was probably a stimulus 

 to them and thereby brought the nerve into action. No such results were obtained 

 from similar experiments on the ampulla' of Lorenzini. but the nerves from the 

 lateral-line system in Raja <-I<n;iiii and R. asterias also gave evidence of transmission 

 when their terminal organs were pressed. Dilute acids and heat did not stimulate 

 the terminal organs tested, and Fuchs (1894, p. 474) concluded that pressure was the 

 normal stimulus in the skate for the lateral-line organs ami in the torpedo for the 

 vesicles of Savi, but not for the ampullae of Lorenzini. 



Apparently without knowledge of (he work done by Fuchs, Richard (1896, p. 

 131) performed some experiments on the gold-fish, consisting of the removal of the 

 scales from the lateral line ami the destruction of the sense organs under these scales 

 by cauterizing with beat, or potaasic hydrate. After this operation some of the 

 fishes were unable to keep below the surface of the water, and Chough they soon 

 died. Richard (1896, p. 133) believed that he had evidence enough to show that the 

 lateral-line organs were connected with the production of gas in the air bladder. 



Richard's conclusions were called in question hy Bonnier (1896, p. i»17), who 

 pointed out the severity of the operations employed and intimated that the results 

 were more probably dependent upon the excessive amount of tissue removed than 

 upon the destruction of the lateral lint 1 . Bonnier (1896, p. '.'is) further recorded 

 experiments of his own in which the lateral-line organs were destroyed by electro- 

 cautery. Fishes thus operated upon showed two characteristics: They could easily 

 be approached with the hand and even seized; and they failed to orient themselves 

 in reference to disturbances caused by bodies thrown into the water. Bonnier con- 

 cluded from his experiments that the lateral line, in addition to other functions, had 

 to do with the orientation of fishes in reference to centers in the water from which 

 shock-like vibrations might proceed. 



Lee (1898, p. L39), whose experimental methods were much the same as those 

 used by Bonnier, obtained some significant results, particularly with the toad-fish, 

 Opsanus t<<u. When the pectoral and pelvic tins of this fish were removed, so that 

 it might be said to lie without its usual mechanical support, and the lateral-line 

 organs were destroyed by thermo-cauterv, the animal would lie quietly for some 

 time, (in either its side or back, and act as though it had lost its' " sense of equilibrium. " 

 That its condition was not due to excessive injury was seen from the fact that a tin- 

 less fish in which an equal amount of skin had been cauterized, but in which the 



