Mutual Influence of Crystalloids of Human Blood Serum on Their Equilibrium

The blood serum is an aqueous (ultramicroscopic)-suspension of colloids in a solution of crystalloids. The crystalloids are under normal conditions in a well balanced equilibrium, which is sustained by the colloids: static equilibrium. A normal blood serum for instance contains 90-120 mg. of dextrose per 100 cc. of blood. The presence of the colloids inhibits even in vitro an increase of this amount within certain (physiological) limits. If we try to increase the blood sugar by adding the physiological amount of 100 mg. per 100 cc. and determine the sugar we find only 25% of the added amount; 75% (60-80%) disappear in the normal human serum. The serum colloids have, therefore, the power to restore and to maintain the equilibrium, if we try to disturb it: dynamic equilibrium. The following studies are based on this observation. The serum crystalloids are electrolytes and non-electrolytes. The influence of changes of the electrolytes as well as of the non-electrolytes on the static and on the dynamic equilibrium of the non-electrolytes of the normal human blood serum has been studied with the following results:

(1) Influence of cations on the static equilibrium of the serum sugar: Chlorides have been used in n/10, n/100 solution, 0.02 cc. added to 1 cc. of serum. NaCl does not influence the blood sugar even in n-solutions. KCl increases the blood sugar (5-10%), CaCl₂ and MgCl₂ do not influence the sugar as a rule, but act differently in different sera. FeCl₃ always decreases the sugar of a normal serum, ca. 10%.

(2) The influence of cations on the dynamic equilibrium of the serum sugar, i. e., after the addition of a physiological quantity (200 mg. per 100 cc.) acts exactly in the same way, but more intensely; NaCl does not influence the loss of the added dextrose, KCl decreases the loss considerably, CaCl₂ and MgCl₂ also decrease the loss, but less than KCl; FeCl₃ always increases the loss of dextrose.