104 SPECIAL PHYSIOLOGY 



piece micrometer. Now inject into dorsal lymph spaces 0.3 c.c. 

 tincture digitalis and measure same arteriole at intervals of ten 

 minutes. Keep the web moist with normal saline solution. 



(a) What change occurs in the diameter of the arteriole? 



(6) What effect would you expect this to have on arterial pressure ? 



(c) Would its action on the arterioles help to account for its effect 

 on arterial pressure? 



(4) Comparisons. Compare digitalis and atropine with regard to 

 (a) their effects on the rate of the heart beat; (6) their effects on the 

 irritability of the vagus. 



XVI. THE ACTION OF ACONITE UPON THE CIRCULATION. 



1. Material. Tincture aconite; sulphate of atropine; one dog; 

 one frog; sphygmograph. 



2. Preparation. Make solution of atropine, 0.02 grm: to 10 c.c. 

 Pith frog. Do not fasten the dog to dog board. 



3. Experiments and Observations. (1) Give 1 c.c. tincture 

 aconite hypodermically to the dog. Record symptoms as they arise. 

 (1 c.c. often not fatal.) 



(2) Fasten the pithed frog on its back to the board. Count the 

 heart beats, exposing heart if necessary. Now give two drops tincture 

 aconite subcutaneously. What effect has aconite on the pulse rate? 

 (To obtain satisfactory results, observations must be made at short 

 intervals, for from thirty to sixty minutes.) 



(3) Take a sphygmographic tracing of the radial pulse of a student. 

 Note the pulse rate. Administer by mouth 0.2 c.c. tincture aconite 

 and 0.06 c.c. every ten minutes until action on pulse is noticeable. 

 Repeat tracing and counting of pulse at short intervals. 



(a) How does aconite affect blood pressure? 



(6) How is the rate of the heart's action affected? 



(c) What subjective sensations are produced? 



(4) Comparisons. Compare aconite arid pilocarpine with regard 

 to their action on the gastrointestinal system. 



XVII. THE ACTION OF ADRENALIN UPON THE CIRCULATION. 



1. Materials. White rabbit; adrenalin. 



2. Preparation. Make solution of adrenalin 0.01 grm. to 10 c.c. 

 of normal saline solution. Weigh the rabbit and fasten it to the 

 holder, and with probang made of absorbent cotton on probe apply 

 solution to cornea; note local effect on peripheral circulation. 



3. Operation. Anaesthetize rabbit, expose carotid, and insert 

 cannula into artery and take blood pressure. Ligate external carotid; 



