Physiology

puncture) and venous blood is difficult to apply to man, and methods of catheterization of the right auricle, however ingenious they may be, can hardly stand the test of ordinary clinical use. Nevertheless, as the author demonstrates, they have their place in the establishment of actual values for standards with which to compare other methods. The indirect Fick method carries an error due to the well-known difficulty of obtaining true alveolar samples of air in actual equilibrium with the blood. Constructive criticism of the results and methods of numerous workers in this field is made. To obviate some of these difficulties, the triple extrapolation method has been devised and proved accurate but laborious. The equilibrium is approached from various points and the true value of the alveolar air is calculated. This method possesses the unique advantage of embodying a criterion for rejecting erroneous data. By some physical measurements relative cardiac output-values can be obtained. Of these, the roentgenographic study of the cardiac silhouette is probably the best, but involves inaccuracies which detract markedly from its value. The fundamental errors of the sphygmograph leave this system open to severe criticism. A fairly comprehensive summary of the foreign gas methods includes the use of nitrogen, nitrous oxide, ethyliodide, ethylene, and acetylene. The last named gas was introduced by the author in 1929. Acetylene is not lipoidsoluble, it is readily diffusible, its solubility is of a convenient magnitude, and its presence is easily determined quantitatively. The taste is not unpleasant and is one to which the patient soon becomes accustomed. The method of election is that based on the rebreathing of an acetylene, nitrogen, and oxygen mixture, and the computations, technic, and apparatus are described in detail. Most of the author's studies have been based on this method, which is as applicable in health as in disease. The book gives the results of many studies of the effect of exercise, digitalis, carbon dioxide, and various other drugs, pregnancy, hyperthyroidism, heart disease, and numerous other states. The reviewer is impressed with the repeated statement-"further studies of the cardiac output are desirable .. to elucidate"-and realizes that this monograph is important not only as a valuable compendium of information but also as a stimulation to further work on the subject of the cardiac output. CARL H. WIES.