186 THE SCIENTIFIC MONTHLY
yariouB kinds of colloids are suspended.^^' Such a suspension involves a play of the energies of the free particles of matter in the most delicate equilibriiun^ and the suspended particles exhibit the vibrating move- ment attributed to the impact of the molecules.^^* These free particles are of greater magnitude than the individual molecules^ in fact^ they represent molecules and multimolecules ; and all the known properties of the compoimds known as ^^ colloids ^' can be traced to feeble molecular afSnities between the molecules themselves^ causing them to unite and to separate in multimolecules. Among the existing living colloids are cer- tain carbohydrates, like starch or glycogen, proteins (compounds of carbon, hydrogen, oxygen and nitrogen with sulphur or phosphorus), and the higher fats. The colloids of protoplasm are dependent for their stability on the constancy of acidity and alkalinity, which is more or less regulated by the presence of bicarbonates.^"
Electrical charges in the colloids*^' are demonstrated by currents of electricity sent through a colloidal solution, and are interpreted by Freundlich as due to electrolytic dissociation of the colloidal particles, alkaline colloids being positively charged while acid colloids are nega- tively charged. The concentration of hydrogen and hydroxyl ions in the ocean and in the organism is automatically regulated by carbonic acid (C0,)."«
Among the colloidal substances in living organisms the so-called enzymes are very important since they are responsible for many of the processes in the organism. Possibly enzymes are not typical colloids and perhaps, in pure form, they may not be classified as such ; but if they are not colloids they certainly behave like colloids.^*^
COOBDINATION OF THE FbOPEBTIES OF THE LiFE ElEHENTS THROUGH
Interaction
We have thus far traced the actions and reactions of the life elements, which are mainly contemporaneous, direct, and immediate ; they do not suflSce to form an organism. As soon as the grouping of chemical ele- ments reaches the stage of an organism interaction becomes essential, for the chemical activities of one region of the organism must be harmo- nized with those of all other regions; the principle of interaction may apply at a distance and the results may not be contemporaneous. This is actually inferred to be the case in single-celled organisms such as the
The interacting and coordinating form of lifeless energy which has
lis Beehhold, Heinrich, 1912.
118 Smithy Alexander, 1914, p. 305.
11* Henderson, Lawrence J., 1913, pp. 157-160.
iiB Loeb, Jacques, 1906, pp. 34, 35.
116 Henderson, Lawrence J., 1913, p. 257.
117 Hedin, Sven G., 1914, pp. 164, 173. us Calkins, Gary N., 1916, pp. 259, 260.
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