202 THE CIRCULATION OF THE BLOOD AND LYMPH 



coil and electrodes for a tetanizing current (Fig. 93, p. 300). With 

 scissors curved on the flat clip away the hair from the front of the 

 neck. Put the hair carefully away, and remove all the loose hairs 

 with a wet sponge so that they may not get into the wounds. Give ether, 

 or pour into the stomach by a tube 5 c.c. of a 0*5 per cent, solution 

 of chloroform, in 10 per cent, alcohol per kilo of body-weight, diluted 

 before administration with 3 or 4 volumes of water (Grehant's method). 



To put a Cannula in the Trachea. The hair having been clipped in 

 the middle line of the neck and the skin shaved, a mesial incision is 

 to be made, beginning a little below the cricoid cartilage, which can 

 be felt with the finger. The trachea is then cleared from its attach- 

 ments by forceps or a blunt needle, and two strong ligatures are passed 

 beneath it. A single loop is placed on each of these, but is not drawn 

 tight. Raising the trachea by means of the upper ligature, the student 

 makes a longitudinal incision through two or three of the cartilaginous 

 rings, inserts the cannula, and ties the lower ligature firmly around its 

 neck. The upper ligature can now be withdrawn. 



Clip off the hair on each side of the sternum. Make an incision on 

 each side through the skin and down to the costal cartilages about 

 2 inches from the edge of the breast-bone, and long enough to expose 

 about four costal cartilages (say, 3rd to 6th). With a curved needle 

 pass waxed ligatures round the cartilages, and tie firmly to compress 

 the intercostal vessels. The bellows should now, or earlier if any 

 symptoms of impeded respiration have appeared, be connected with 

 one end of the horizontal limb of a glass T-piece, the other end of 

 which is similarly connected with the tracheal cannula. The stem of 

 the T-piece is provided with a short piece of rubber tubing, which, 

 when artificial respiration is being carried on, Is to be alternately closed 

 and opened closed during inflation of the lungs, and opened when 

 the air is to be allowed to escape from them. Or a screw-clamp may 

 be adjusted on the piece of tubing so that the opening is sufficiently 

 narrow to permit the lungs to be properly inflated when the bellows 

 are compressed, and yet sufficiently wide to permit easy escape of the 

 air and collapse of the lungs at the end of each inflation. Ether may, 

 when necessary, be administered, by inserting between the T-piece and 

 the tube from the bellows an ether bottle with two tubes passing through 

 the cork to within an inch or two of the ether. If the cannula has a 

 side-opening, as is usually the case v/ith metal cannulae, the T-piece 

 may be dispensed with. One student should take sole charge of the 

 artificial respiration, which ought to be begun as soon as the chest has 

 been opened, and continued at the rate of about twenty inflations 

 per minute. The costal cartilages are rapidly cut through with strong 

 scissors just on the sternal side of the ligatures, the artificial respira- 

 tion being suspended for an instant, as each cut is made, to avoid 

 wounding the lungs. The sternum is divided at its lower end and 

 turned up. If there is much bleeding a ligature should be tied round 

 its tipper end. With a curved needle a ligature is passed below the 

 internal mammary arteries as they approach the sternum. That bone 

 may now be removed, and the heart, enclosed in the pericardium, comes 

 into view. A thread is passed with a suture-needle through each side ol 

 the pericardium, which is then stitched to the chest-wall and opened. 



(a) Note the various portions of the heart, right and left ventricles, 

 right and left auricles, with the auricular app.ndices. Feel the heait 

 with the hand, and observe that the right ventricle is softer and has 

 thinner walls than the left, and that the auricles are softer than the 

 ventricles. Note how all the parts of the heart harden in the hand 

 during systole and soften during diastole (pp. 86, 90). 



