94 Bulletin of Laboratories of Denison University, [voi. xii 



ADDENDUM. 



During the winter and spring of 1903 some further obser- 

 vations have been made with the purpose of answering (among 

 others) the question raised above, whether fishes can locaHze 

 a sensation received by the terminal buds alone with no tactile 

 accompaniment, or, in other words, whether gustatory sensa- 

 tions may be provided with a local sign as tactile sensations are. 

 (This question, of course, does not necessarily involve the 

 more general one as to the essential nature of the local sign, 

 whether it is due to a "specific energy" of the peripheral nerve 

 or sense organ or to central differentiation in the terminal nu- 

 cleus.) 



Some recent clinical observations suggest that in human 

 beings such a localization of gustatory sensations is possible. 



Gushing {/o/ms Hopkins Hosp. Bull., XIV, No. 144, 

 1903, p. yy) reports after destruction of the Gasserian ganglion 

 and total paralysis of general sensation on the anterior part of 

 the tongue, that the gustatory sensibility remains unimpaired 

 and that in this case the gustatory sensations can be localized. 

 It is not, however, absolutely certain that it is the gusta- 

 tory fibers which effect the localization, for the chorda tympani, 

 which was uninjured, may carry also a certain number of fibers 

 for general sensation from the facialis root in addition to gusta- 

 tory fibers, as Gushing assumes is the case with the chorda 

 from some of his results and from those of Koster. 



My own observations were made on the young of Ameiu- 

 rus from five to eight cm. long, received from the state fish 

 hatchery at London, O., in October, 1902, and kept under ob- 

 servation in tanks during the following winter. These fishes 

 prove to be more shy and less teachable than the smaller 

 Ameiurus fry (about three cm. long) hatched by wild parents 

 upon which the experiments reported in the preceding pages 

 were made. 



I have verified upon these fishes most of the observations 

 made on the smaller fishes last year. The most noticeable dif- 

 ference in their behavior is the evidently greater visual power 

 in these fishes. As soon as they began to feed freely in the 



