THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. V, No. 4] OCTOBER, 1909. [^oI^xVnT* 



A STUDY OF THE RESPIRATORY AND CARDIAC AC- 

 TIVITIES AND BLOOD PRESSURE IN THE SKATE 

 FOLLOWING INTRAVENOUS INJECTIONS OF SALT 

 SOLUTIONS. 



BY IDA H. HYDE. 



Plate X, and 49 figures. 



(From the Marine Biological Laboratories of Woods Hole and Leland Stanford' and the 

 Physiological Laboratory of the University of Kansas.) 



' I ''HE experiments that are recorded in this article were con- 

 * ducted on the skate, Raia erinacea and Raia binoculata, 

 during the summers of 1902, 1903, 1906 and 1907. 



A host of articles have accumulated since Humboldt first 

 studied the action of salt solutions upon the rhythmical changes 

 in the heart's contractions ; but with the progress of physical 

 chemistry new problems and different views presented them- 

 selves and left many important questions still unsettled. To 

 aid in solving some of these I undertook the study from a less 

 general standpoint by employing a method and an animal sel- 

 dom heretofore adopted in the solution of the questions. A 

 few experiments were begun on the fresh-water sturgeon and 

 on the frog in order to compare the results with those obtained 

 with the skate. These, however, will be extended and varied 

 before the results are published. 



It was hoped that simultaneous records and comparisons of 

 the three activities might throw some light upon the factors 

 that influence them and indicate whether their nerve centers 

 are alike stimulated by the same ions. At first the object was 

 also to determine whether it was the anion or cathion that 



1. I take this opportunity to express my hearty thanks to the directors for the priv- 

 ilege of working in these institutions and for the courtesies I received there. 



(29) 



