Umbilic Hemorrhage ■ 1037 



and the lungs fail to become inflated. If one would be sure of 

 the introduction of the air into the lungs, it would be best to in- 

 troduce it into the trachea, and close the nostrils and mouth so 

 that it could not escape in that way. In some cases, where the 

 larynx seems to be occluded and it is impossible to induce free 

 breathing through that organ, it might be well to perform 

 tracheotomy, until whatever obstruction existing in the larynx 

 may be removed. Ordinarily tracheotomy of the newborn involves 

 great danger of tracheal collapse later, and is accordingly to be 

 avoided as far as possible, and, instead, an incision made through 

 the crico-thyroidean liagament large enough to admit the oper- 

 ator's finger 



2. Umbilic Hemorrhage. 



Umbilic hemorrhage in the new-born animal is very rare. We 

 have not had occasion to observe this accident in any case. 

 Under normal conditions, when the umbilic arteries rupture they 

 retract within the abdominal cavit5', as shown in Fig. 56, and in 

 so doing withdraw with them, in an inverted manner, the con- 

 nective tissue surrounding them, and thus form a net-work of 

 fibers, which serves to cause the blood to coagulate and make 

 hemorrhage extremely improbable . The retraction of the arteries 

 also causes a thickening of their walls, and a distinct decrease in 

 their caliber, thereby so narrowing the lumen that it is exceed- 

 ingly difficult for blood to escape from their divided ends. In 

 addition to this, there is a general physiologic law that the blood 

 pressure is decreased whenever the blood is no longer required 

 by the tissues. Since the function of the umbilic' arteries has 

 ceased, the blood pressure within them becomes suddenly de- 

 creased . 



Fleming states that hemorrhage may take place from these 

 arteries in the foal, because they are firmly attached to the um- 

 bilic ring. After repeated autopsies, we have failed to find 

 an instance where such was the case, except the umbilic cord 

 had been ligated, and the arteries thereby held so firmly that 

 they could not retract. In addition to this, when the cord is 

 ligated it is usually divided at an abnormal distance from the 

 umbilic ring, so that its retraction is difficult. In all foals which 

 we have examined, where the navel cord had been allowed to 

 rupture normally, the arteries had promptly retracted to the 



