INTERNAL SECRETIONS. 



done with strict asepsis. The instruments should be boiled, liga- 

 tures sterilized, and hands cleansed and soaked in the bichloride 

 solution. 



Expose the trachea through a median cervical incision, carrying 

 the incision as far as the thyroid cartilage. Pull aside and sepa- 

 rate, by blunt dissection, the longitudinal neck muscles from the 

 thyroid lobe of one side. This is seen as an oval, reddish mass. 

 With blunt hooks and scalpel handle separate it from its attach- 

 ments. Tie all blood-vessels with two ligatures and cut between. 

 The thyroid branch of the carotid artery should not be tied too 

 near its origin, since there is danger of the ligature slipping later, 

 and secondary hemorrhage. If an isthmus is present connecting 

 the two lateral lobes, this also should be removed. 



The wound is now cleansed with sterile o.8-per-cent NaCl solu- 

 tion, dried, and closed by two rows of interrupted silk sutures, one 

 to draw the muscles together over the trachea, the other to approx- 

 imate the skin. Cover the wound with a thin layer of sterile ab- 

 sorbent cotton and paint with collodion. 



Keep the animal under careful observation for ten days or two 

 weeks, recording the weight daily. At the end of this time, repeat 

 the operative procedure and remove the remaining thyroid lobe. 

 Keep under careful observation, recording the weight daily, taking 

 the temperature per rectum, and counting the red and white cor- 

 puscles of the blood. Note all symptoms and keep a careful record 

 until death occurs. If the animal does not die or show the charac- 

 teristic symptoms of thyroid removal, all the thyroid has not been 

 removed or there are accessory thyroids present. This may be de- 

 termined at autopsy later. 



At autopsy the condition of all the organs should be determined 

 and the field of the operation examined to see if the thyroid re- 

 moval was complete and if accessory bodies are present. These 

 are sometimes found in the neck region near the thyroid lobes 

 proper, or in the mediastinum. If found, they should be hardened, 

 embedded, sections cut, stained, and examined for thyroid struct- 

 ure 



