156 OTHER PULSATORY PHENOMENA. 



instance, due to calcification, the propagation of the pulse-wave must be more 

 rapid. Local dilatation of the arteries, such, for example, as has long been 

 known in the form of aneurysms, cause a retardation of the pulse-wave ; local steno- 

 sis has a similar effect. Relaxation of the vessel-walls during high fever retards 

 the movement of the pulse- wave. 



In Accordance with what has been said concerning the course of the recoil- 

 wave, its time of appearance must also be affected by the differences mentioned. 



FIG. 62. Tracing from the Ulnar Artery on a recording surface Attached to a Vibrating Tuning-fork (i = 0.01613 

 sec.): P, the apex of the curve; e e, elasticity- vibrations; R, recoil-elevation; B, curves from the same ulnar 

 artery, taken at the same time with v H P = the ventricular contraction of the same individual. 



It must appear earlier when the blood-pressure is raised, and also in atheromatous 

 than in healthy arteries; but relatively late in the elastic arteries of the child. 

 The latter point was determined by Landois by mensuration. While in a man, 

 30 years of age and 172 cm. in height, the apex of the recoil-elevation was reached 

 0.387 second after the beginning of the radial curve, Landois found that the apex 

 in a girl, 8 years old and 103 cm. in height, occurred at the end of 0.387 second, 

 evidently indicating a relative delay. 



OTHER PULSATORY PHENOMENA. 



Oral and Nasal Pulse; Tympanic Pulse. In consequence of the pulsatory 

 movement in the arteries of the soft tissues, the air contained within the oral 

 and nasal cavities is also set into pulsating movement when the glottis is closed, 

 and which can be registered with the aid of the cardiopneumograph. The tracings 

 obtained in this way, and which must closely resemble the sphygmographic 

 tracings from the carotid artery, are of course relatively small, but they can be 

 made larger by increasing the force of the heart. This pulse may be considerably 

 intensified in the presence of pathological enlargement of the heart, dilatation 

 of the left ventricle and thickening of its walls. If a ring containing a soap- 

 bubble be inserted hermetically between the lips, the light-reflex in the bubble 

 (seen in a mirror) reproduces almost perfectly the oscillations of the oral pulse. 

 As a result of the systolic swelling of the vascular soft parts in the tympanic cavity 

 analogous pulsation may be observed in the intact drumhead, or possibly in small 

 bubbles of froth accidentally adherent to openings in a perforated membrane. 



If the visual field be darkened, each pulse-beat during violent exertion is often 

 accompanied by a pulsatory illumination. Conversely, if the visual field be brightly 

 illuminated, a corresponding obscuration of the field may take place. Pulsation 

 is sometimes observed in the retinal arteries with the ophthalmoscope, especially 

 in cases of aortic insufficiency. 



The orbicularis palpebrarum muscle under similar conditions contracts syn- 

 chronously with the pulse. This contraction appears to be due to the fact that 

 the beat of the pulse excites the sensory nerves and reflexly causes a contraction. 

 In this connection attention should be called to an observation made by the 

 brothers Edward and William Weber, which seems to be in accord with this point. 

 They found that, in walking, the pulse and the step not infrequently coincide. 

 Landois believed that this phenomenon may be explained by assuming that the 

 pulse-beat stimulates the muscular mass of the thigh into contraction, to which 

 gradually all the muscles of the thigh accommodate themselves at each step. As 

 the blood-vessels dilate while the muscles are contracting and the movement of 

 the venous blood is accelerated, the coincidence of pulse and step has the addi- 

 tional advantage that the mass of blood to be moved, which is greater during the 

 pulse-beat, is thereby better enabled to pass through the masses of muscle-tissue. 



