THE EEACTIONS OF THE DOGFISH TO CHEMICAL 



STIMULI. 



BY 



RALPH EDWAIU) SHELDON. 



Contribiitioii from the Woods Hole Lahomtonj of the United Htutes 

 B II lean of Fisheries* 



With Tiikee Figures. 



TABLE OF CONTENTS. 



P.\GB 



Introductory 273 



Conditions of experinioutatioii 27(> 



Reactions obtained 278 



Sensitiveness to cliemical stimuli. 



Experimental results 281 



Analysis of results 281 



Operations. 



Destruction of the spinal cord 288 



Transection of the spinal cord 289 



Innervation and reactions of the nostrils 291 



Chemical sensation as a sense quality 294 



Conclusions 29-1 



Summary 297 



Bibliography 299 



Figures 308 



Introductory. 



The smooth dogfish, Mustelus eaiiis (Mitchell), was the subject 

 of experiment in an endeavor to find ont the sensitiveness of the gen- 

 eral body sni-face to chemical stimnli and the extent to which the 

 nerves of general sensation share in the reactions called forth through 

 stimulation of the mouth and nostrils. In the investigation of these 

 problems certain accessory points, such as the spinal animal and the 

 innervation of the olfactory capsules, are taken up. The substances 



*Published by permission of George ISI. Bowers, U. S. Commissioner of 

 Fisheries. 



The Journal of Comparative Neurology and Psychology. — Vol. XIX, No. 3. 



