100 PULSE RECOKDS IN THEIR RELATION TO 



this view is as follows : The proof of the occurrence of the second 

 positive wave in the auricle is not considered as final l ; tracings 

 of an obviously arterial nature are obtained with the greatest 

 ease from many points of the neck ; as the receiver is moved 

 higher in the neck the tracing gradually acquires the arterial 

 character and eventually loses all trace of jugular waves ; the 

 wave is said to be synchronous with the primary wave of the 

 carotid pulse ; it is occasionally absent from the jugular tracing 

 when the latter has a large amplitude ; 2 it is said to be absent 

 from a type of liver pulse known as the auricular liver pulse. 



There are many observations in opposition to this evidence. 

 Morrow ( 37b ) finds that clamping the carotid near its origin does 

 not affect the wave. 3 Fredericq ( 12c ) states that in animals the 

 wave persists when the artery is completely separated from the 

 vein from which the record is taken. Bard ( lb ) has also noted the 

 " c " wave in a subclavicular vein, isolated from all arteries, and 

 Rautenberg has recorded it in its full dimensions in the superior 

 vena cava of a dog. Hering states that in heart bigeminus where 

 the second pulse beat has a longer presphygmic interval than the 

 first, there is no corresponding delay in the appearance of the 

 " c " wave in the neck. 



There can be no doubt that in many tracings of the jugular 

 pulse the arterial shock contributes to the " c " wave ; the diffi- 

 culty is frequently in avoiding the arterial pulsation. The main 

 question is as to whether it is the only factor, or as to whether 

 on occasion it may contribute but slightly or even take no part 

 in its production. The character of the wave is of importance. 

 In many tracings it is very prominent and peaked, and shows 



1 This question has already been dealt with as fully as space will permit. 

 It is questioned if the apparatus used in recording auricular pressures may not tend 

 to the production of the wave. The apparatus has varied very greatly, as has 

 also its position in the process of recording ; yet the majority of the curves show 

 the same characters. Porter has registered the wave in the pulmonary veins, and 

 Rautenberg in the superior vena cava ; more recently Delchef has recorded the wave 

 in the inferior vena cava (Archiv. Internal, d. Physiol., vii. 1908, p. 96). 



* Hering (**) explains this by the magnitude of the " a " wave in the tracings 

 given, and states that the " carotid shock " may also disappear. 



3 Morrow holds that the essential part of the " c " wave is conducted from the 

 auricle where it may be produced by 



1. A force exerted during ventricular systole, through the auriculo- ventricular 

 valves. 



2. Contraction of the ring of muscle in the auriculo-ventricular junction. 



3. Pressure exerted upon the auricles by the systolic twist of the heart. 



