542 ON PULSATION IN THE JUGULAR AND OTHER VEINS. 



animal, all the cavities of the heart continued to beat for a 

 considerable time after the thorax had been opened. The 

 ventricles then stopped, but the auricles continued to pulsate, 

 as well as the pulmonary veins. The veins nnd auricles both 

 pulsated at the rate of 119 per minute, but the contractions 

 were not synchronous. The auricles then ceased to beat, but 

 pulsation continued in the pulmonary veins, and the ventricles 

 again commenced, although the auricles remained perfectly 

 quiet. The pulsation of the ventricles was at the rate of 8 per 

 minute; while in the pulmonary veins it was at the rate of 

 46 per minute. Both the superior and inferior vena cava in 

 the same animal were found to be pulsating an hour and forty 

 minutes after the thorax had been opened. From the inferior 

 cava contraction spread like a wave over the right auricle, the 

 ventricle being quiet. But after the auricle had contracted 

 two or three times, the ventricle again commenced to pulsate. 

 These rhythmical contractions of the pulmonary veins, and of 

 the vena cava, occur in animals killed in various ways. Sir 

 Joseph Fayrer and I observed them in animals killed by a blow 

 on the head, by the action of cobra poison, and by the com- 

 bined use of chloroform, atropia, and physostij^ma. They do 

 not occur frequently, and the conditions under whicli they take 

 place are at present unknown, and we are unable to say 

 whether th^y occur in man at all. But it has been shown by 

 observations on decapitated criminals that the inferior vena 

 cava, as well as the hepatic, portal, and several of the sub- 

 pleural pulmonary veins, besides others, are strongly contractile. 

 It seems, therefore, not improbable that such contractions may 

 occasionally occur in the human subject. In one case, as I 

 have already said. Sir Joseph Fayrer and I noticed that the 

 contraction of the pulmonary veins was not synchronous with 

 that of the auricles. The ventricles, at this particular time, 

 were not pulsating, but, had they been doing so, their contrac- 

 tions must needs have been synchronous with those of the 

 pulmonary veins. Supposing that in a case of mitral regurgita- 

 tion a similar rhythmical contraction should occur in tlie 

 pulmonary veins, a most powerful obstacle would be opposed to 

 the backward flow of the blood, and the force of the current, 



