BODY TISSUES AND FLUIDS 459 



fants the figures are about 10 c.c. lower than in adults. With moderate 

 acidosis, in which symptoms may or may not be apparent, CO 2 combin- 

 ing power figures of 30 or below are found. In the terminal stages of dia- 

 betic coma figures of 10 to 15 c.c. are encountered, and similar figures 

 are sometimes observed in "uremia." In such cases death may be di- 

 rectly ascribed to the acidosis. Extremely low figures are encountered in 

 many cases dying from pneumonia. Low figures may likewise be obtained 

 in the diarrhea! acidoses of infancy. All cases of chronic nephritis with 

 marked nitrogen retention show a moderately severe or a severe acidosis, 

 while occasionally severe acidosis is encountered in acute nephritis. Ether 

 anesthesia is accompanied by a fall in the CO 2 combining power of the 

 blood, amounting to 2 to 20 volumes per cent. The introduction of a 

 simple method of estimating the CO 2 combining power of the blood has 

 placed the diagnosis and treatment of cases of acidosis on a rational basis. 



Muscle 



The muscle tissue of the human adult has been variously estimated 

 as comprising from 30 to 40 per cent of the body weight. Of the total 

 body metabolism about 50 per cent takes place in the muscles during rest 

 and 75 per cent during activity. Physiologically, muscle tissues are di- 

 vided into voluntary or striated and involuntary or non-striated muscle, 

 heart muscle belonging to an intermediate group. The involuntary muscles 

 comprise only a comparatively small part of the total muscle tissue. The 

 muscle fibers of which muscle tissue is chiefly composed are elongated, 

 spindle shaped cells. Muscle tissue in the adult contains from 22 to 28 

 per cent solids with an average of 25 per cent. Of this about four-fifths 

 is protein and the remainder largely extractives and inorganic salts. 



The proteins of the muscle are ordinarily divided into two groups, 

 the muscle plasma and the muscle stroma. This division or separation 

 is a more or less arbitrary one, since the muscle plasma simply represents 

 the amount of protein which can be expressed (about 60 per cent) from 

 fresh muscle. In the muscle plasma there are two distinct proteins, as 

 may readily be shown by the fractional coagulation of the plasma. Para- 

 myosinogen (Halliburton (a)) or myosin (von Fiirth(a)) coagulates at 46- 

 51C., while myosinogen or myogen coagulates at 55-65 C. The former 

 constitutes about 25 per cent of the protein in the plasma and the latter 

 75 per cent. The first of these proteins is definitely a globulin, but the 

 latter is not a typical globulin since it is soluble in water, and belongs 

 rather to the class of albumins. The proteins of different muscles do not 

 differ widely in their content of amino-acids. The phenomenon of rigor 

 mortis, according to the now generally accepted view, first suggested by 

 Meigs, is due to the swelling of the muscle cells (taking up of water) 



