544 FRANCIS W. PEABODY AND EDNA H. TOMPKINS 



incomplete breakdown of the many amino acids are manifold but largely 

 uninvestigated. 



Of the metabolism of fat in asphyxia! conditions little is known except 

 the general clinical fact that in certain diseases where the supply of oxygen 

 is limited there is an increase in fatty tissue, "a fatty infiltration," as 

 Lusk designates it, and the few reports of Ryffel as to the appearance of 

 acetone bodies in some instances. 



Most disturbances of the intermediary metabolism due to oxygen-lack, 

 therefore, tend to produce acidosis. In fact, it is generally assumed, 

 from the lowered carbon dioxid tension of the alveolar air and carbon 

 dioxid combining power of the blood, in cases where normals are subjected 

 to low oxygen pressure, that acidosis is present. Thus, as a last point 

 of attack, the effect of acidosis itself upon the metabolism must be con- 

 sidered. Acidosis increases the total metabolism, as has been shown by 

 Lusk and Benedict and Joslin. It increases the nitrogen output, and 

 thus also the sulphur, with a large ammonia percentage (Lusk; Bostock; 

 Stehle; von Limbeck; and Sawyer, Baumann and Stevens). It causes a 

 larger output of creatin than normal (Sawyer et al.) and, from the work 

 of Goto, Sawyer et al., and Stehle, it increases the mineral metabolism, 

 especially of the calcium and phosphorus, and somewhat less of the sodium 

 and potassium. 



Under normal conditions, as has been indicated, there is a complete 

 and harmonious interaction between the circulatory and respiratory sys- 

 tems, and their activity is largely regulated by the body metabolism. Both 

 the respiration and the circulation are endowed with great reserve force 

 which enables them to meet the requirements of the metabolism when it 

 is raised many times above its resting or basal value. Thus, during severe 

 exercise, the pulmonary respiration becomes deeper and quicker, so that 

 the alveolar ventilation is increased. At the same time the heart beats 

 more rapidly, delivers a larger output, and raises the circulation rate. 

 As a result of this and associated vasomotor adjustments, the blood flow 

 through the tissues is greatly augmented, an adequate supply of oxygen 

 is provided and the waste products of metabolism are removed. This 

 reserve power has a special significance in the diseases of the respiration 

 and circulation, for it explains the fact that only when they are severely 

 affected is there any interference with their normal function at rest. 

 Pathological conditions affecting the respiration or circulation begin by 

 causing a reduction of the normal reserve, so that the needs of the metab- 

 olism cannot be met if it is greatly increased. This is seen, for instance, 

 in emphysema, or in early valvular heart disease, in which the metabolism 

 at rest is carried on normally and without discomfort,, but in which even 

 moderate exercise may produce dyspnea indicating an imperfect gaseous 

 exchange. It is only when the pathological process has advanced so that 

 the reserve power of the circulation and respiration has been greatly 



