CIRCULATION. Ill 



or a seeker the delicate intermuscular connective tissue. 

 A blood vessel and several nerves come into view. 



Is the blood vessel an artery or a vein ? How many 

 large nerves accompany the blood vessel ? 



Take hold of the sheath of the vessel, lift it up and 

 note in the connective tissue accompanying the blood 

 vessels two nerves, one large and one small. When the 

 artery is in its normal position, what relation do these 

 two nerves sustain to it? Which of the two nerves is 

 external and which is dorsal to the bloodvessel? Which 

 is in close relation to the artery? What is the name of 

 each of the nerves? 



In preparing the nerve for stimulation one should 

 neither grasp it with the forceps nor with the fingers. 

 It may be separated from the delicate connective tissue 

 in which it lies by use of a blunt seeker. Far better 

 than any metallic instrument is a small glass rod drawn 

 to a point, curved and rounded in the Bunsen lamp 

 (see Fig. 11-A). Prevent the tissues drying up by 

 occasionally pressing them lightly with pledgets of 

 cotton moistened with normal salt solution. 



Adjust the electrode carefully upon the vagus and see 

 that no unnecessary tension is allowed to be exerted 

 upon the nerve. It is usually necessary to hold the 

 electrode in place during the observations. 



Observations, 

 a. Anesthesia. (Observations by Group "0.") 



(1) Are you able to make out different stages in anaes- 

 thesia? 



(2) How many stages did your animal manifest? 



(3) Give the characteristics of each stage. 



(4) What effect did the ether have upon the rate of 

 heart beat? 



(5) What effect did the ether have upon the respira- 

 tion? 



