214 COLLOIDS IN BIOLOGY AND MEDICINE 



surface development, unite the advantages of the solid condition with 

 that of the fluid; observe for a moment a mountain climber, a fever 

 patient, or a tree in the springtime, which is decked with leaves 

 in four or five days. What enormous amounts of chemical energy 

 are expended by the mountain climber in a few hours, what large 

 quantities of protein are in a short time consumed by the fever patient, 

 what large quantities of material are carried to and from the periph- 

 ery of the tree. With the least loss of time the reserves must be 

 mobilized and carried to the seat of war, the places where they are 

 consumed. Such a rapid mobilization is unthinkable in the case of 

 a solid crystalloid, with its small surface; a chemical process in a 

 swollen colloid may only occupy minutes, whereas the same reaction 

 in a shrunken colloid requires days. 



How wonderful by means of adsorption is the action of surface 

 development as a regulating mechanism. Luxus consumption of foods, 

 salts, oxygen, etc., are excreted as quickly as possible by the colloid 

 components of the body, but when the supply ceases, the amount 

 given off becomes less and when there is a deficiency the organism 

 tenaciously retains the last traces for its time of need. 



Quantitatively, the substance most important for the organism is 

 water; colloid and water are one in the organism; an organism 

 without water is lifeless. We can imagine such an intimate and 

 varying relation to water only in a colloid system; the process of 

 swelling, the adsorption of water, and shrinking to complete dryness 

 exhibit no leaps or sudden changes in condition. If we compare 

 crystalloids with colloids, we shall see that something entirely new 

 with very changed properties, a solid crystalloid precipitate, appears 

 from a solution upon losing water. Such a system would be unable 

 to maintain correctly the constantly oscillating water balance and 

 the normal condition of swelling in the organism, or to act as an 

 accumulator of large quantities of water, like muscle, and release it 

 for use when necessary. Such a system could not, like a pen, smooth 

 out the irregular chemical impulses, which the organism experiences 

 as the result of physiological and pathological life processes, and 

 which, after absorption, constantly restores its state of swelling to 

 normal by means of secretion (kidney, skin, etc.). 



W T e thus see that the processes which cause us to marvel at the 

 wonderful adaptability of Nature rest upon the simple laws applicable 

 to colloids. Thus it is that I am unable to imagine that the com- 

 plicated and adaptive phenomena of Life could possibly be associated 

 with any other than a colloidal system. 



