888 



SCIENCE. 



[N. S. Vol. XXI. Xo. 545. 



mined by palpation or by the manometer 

 curve does not coincide with complete stop- 

 page of the heart. AVe saw restoration up 

 to forty-four minutes after the pulse ceased 

 to be felt. Doubtless the period of com- 

 plete stoppage was shorter. 



Before proceeding further it seemed ad- 

 visable to determine the limit after which 

 resuscitation is possible in particular or- 

 gans and tissues, especially in the brain 

 and cord. In cats the chest was opened 

 and the innominate and left subclavian 

 arteries, and the aorta immediately below 

 the origin of the left subclavian, were 

 clamped. Artificial respiration was main- 

 tained. The heart continued beating well 

 for a considerable time. The reflexes dis- 

 appeared lasually in ten to thirty-five sec- 

 onds, the respiration about the same time, 

 a few gasps following for a minute or two 

 more. The innominate and left subclavian 

 were released after varying intervals, the 

 aorta remaining clamped. The functions 

 of the anterior part of the animal (in- 

 cluding the brain and cervical cord) re- 

 turned after an interval which was longer 

 the greater the period of occlusion, hnt de- 

 pendent also on the efficiency of the cir- 

 culation. The longest interval after which 

 complete restoration (including voluntary 

 movements, eye reflexes, etc.) has been 

 hitherto obtained is twenty-five and a half 

 minutes. After a fifty minutes' occlusion* 

 excellent respiratory movements returned, 

 together with strong reflex movements of 

 the fore limbs, including good crossed re- 

 flexes, jaw reflexes and violent general 

 spasms of the whole anterior part of the 

 animal. The eye reflexes were not restored 

 nor were we certain that any voluntary 

 movements returned. 



The symptoms appear in a fairly definite 

 order: (1) some constriction of the pupil; 

 (2) twitching of skin over shoulders, on 



'* This experiment was peiformod after the pres- 

 entation of our paper. 



lower jaw or head or in the tongue; (3) 

 gasping movements of jaws rapidly in- 

 creasing in intensity and rate, and soon in- 

 volving neck, shoulders, chest and fore 

 limbs; (4) eyelid, light, and fore limb re- 

 flexes, the latter first confined to the limb 

 struck, but later crossed. The reflex ex- 

 citability of the anterior portion of the 

 cord is abnormally great; (5) extensor 

 spasms of fore limbs, neck and head 

 (usually opisthotonus) ; (6) voluntary 

 movements of head, eyes and limbs. 



We do not know whether animals after 

 such a long period permanently survive. 

 A cat in which all symptoms of complete 

 anemia of the anterior part of the body 

 were present for five minutes after occlud- 

 ing the innominate and left subclavian 

 arteries, artificial respiration being kept up 

 through a tube inserted through the glottis, 

 recovered completely, although the extensor 

 spasms after the anesthesia had passed off 

 were marked. Another cat after ten min- 

 utes' complete anemia had severe spasms 

 and croupy respiration for some hours. 

 The spasms and dyspnoea do not depend on 

 any lack of oxygen in the blood, shown by 

 the appearance of the gums, tongue, etc., 

 and they are not relieved by oxygen in- 

 halation. This animal rapidly recovered, 

 showing only some paralysis of the right 

 limbs, which gradually improved. 



Some preliminary experiments have been 

 made on the maintenance of an artificial 

 circulation through the isolated head with 

 the view, among other points, of ultimately 

 investigating the question of cerebral vaso- 

 motors. In one case the eye reflexes were 

 still obtained with artificial circulation of 

 defibrinated blood after about nine min- 

 utes. As the blood had been kept in the 

 ice box for twenty-four hours after being 

 used for a previous experiment, and as this 

 was one of our earlier experiments, there 

 is no doubt that a much better result can 



