HO A MANUAL OF PHYSIOLOGY 



experiments, pulsation returned in certain parts of the heart, while 

 twenty hours after death from double pneumonia the heart of a 

 boy three months old was restored, and went on beating for over 

 an hour. He obtained also more or less complete restoration of 

 the beat in the hearts of persons dead from bronchitis combined 

 with peritonitis or meningitis, and from cholera infantum, but was 

 unsuccessful in cases of diphtheria complicated with septicaemia 

 or erysipelas, and in cases of pleurisy with effusion. It is to be 

 remarked, however, that although beats of a kind can be obtained 

 a long time after death, they are either confined to the auricles 

 or to portions of them, or, if they involve the ventricles too, they 

 are only shallow and local contractions, especially seen in the 

 neighbourhood of the larger coronary vessels, and are utterly 

 inadequate to the maintenance of an efficient circulation. The 

 heart can also be resuscitated in situ for some time after complete 

 stoppage without the injection of any solution by clamping the 

 aorta in the thorax and practising direct cardiac massage, the 

 lower end of the animal at the same time being elevated to allow 

 blood to pass out of the engorged abdominal veins to the right 

 auricle. The clamping of the aorta permits a sufficient pressure 

 to be attained for the filling of the coronary arteries. The 

 injection of adrenalin into the blood has also been recom- 

 mended as a means of raising the blood-pressure by constricting 

 the small arteries, and stimulating the action of the cardiac 

 muscle. The possibility of restoration of the mammalian 

 heart many hours after somatic death has been considered by 

 some a strong argument for the myogenic theory of cardiac 

 automatism, since, they say, it is improbable that ganglion-cells, 

 elsewhere such physiologically fragile structures, should in the 

 heart retain their vitality for so long a time. But it is easy to 

 overdo this argument, and we must not assume without proof 

 that ganglion-cells in all parts of the body have an equal capacity 

 of survival. Indeed, we know that there are great differences, 

 the nervous mechanism concerned in respiration, e.g., being 

 capable of restoration when the circulation is renewed after 

 total anaemia of the brain and cervical cord lasting for as much 

 as an hour (in cats), while the nervous mechanism concerned 

 in voluntary movements cannot be completely restored even 

 after a much shorter interval. It is very probable that the 

 cardiac ganglia, if the all-important automatic function of the 

 heart depends upon them, are, like the cardiac muscle, endowed 

 with exceptional powers of resistance to those changes which con- 

 stitute death. The possibility also must not be overlooked that 

 the contractions obtained after such long intervals are not truly 

 automatic, but similar rather to the rhythmical beats developed 

 under the influence of pressure in the frog's apex preparation or 

 by immersion in salt solutions of tortoise ventricle strips. 



