. A text-book of human physiology . THE AIITERL\L PULSE 215 be regulated by means of another screw. The whole apparatus is fastened bymeans of a band to the lower end of the forearm (Fig. ST). Many modificationsof this insti-ument are in use. The method of air transmission is often used also, especially when it isdesired to register the pulse eui-ves of two or more arteries, or the pulse curveand cardiogram, at the same time. A receiving tambour of about the same con-. FiG. 87.—Mareys sphygmograph as used. struction as that described for the apex beat is fastened over the arteiy and isconnecte
. A text-book of human physiology . THE AIITERL\L PULSE 215 be regulated by means of another screw. The whole apparatus is fastened bymeans of a band to the lower end of the forearm (Fig. ST). Many modificationsof this insti-ument are in use. The method of air transmission is often used also, especially when it isdesired to register the pulse eui-ves of two or more arteries, or the pulse curveand cardiogram, at the same time. A receiving tambour of about the same con-. FiG. 87.—Mareys sphygmograph as used. struction as that described for the apex beat is fastened over the arteiy and isconnected in the usual way with the recording tambour (cf. Fig. 10, page 12). The sphygmograph has ofien been tested and it has been found to give thepulse movements with surprising accuracy. It has been shown, for example,that it reproduces very exactly the waves, already known, by other means, tooccur in an elastic tube (Mach); that the pulse curve has exactly the sameappearance when the pulsations are recorded without magnification and wherethe inertia of the lever is thus reduced to a minimum (Marey) ; and that pulsecurves having exactly the same form as those recorded by the sphygmograph, areobtained if a very small mirror is fastened to the skin over an artery, so thatthe light may be reflected on a wall. But we must not suppose that every sphygmograph records pulse waves soperfectly. It often happens on the contrary that the instrument distorts thecurve consid
Size: 2520px × 992px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectphysiology, bookyear1
