The migration of drugs in the body, and consequently their action, is largely dependent on their diffusibility through colloidal membranes and their interaction with colloidal bodies. Since I wish to present the action of a colloidal compound of strychnin, it may be of interest at first to give a brief summary of the properties of colloids.1
In 1861, Graham found that not all substances acted in the same way when their solutions were separated from water by a parchment membrane. Crystalline substances like sodium chlorid, potassium iodid, sugar and the like passed through, while substances like gums, starches and proteins did not. Those that passed through he called crystalloids, those that did not, colloids.
This difference in diffusibility is perhaps the most striking distinction between the two classes of substances; it is not, however, the only one nor is it an absolute one, since all these bodies diffuse to
McGUIGAN H. A COLLOIDAL COMPOUND OF STRYCHNIN AND ITS PHARMACOLOGY. JAMA. 1914;LXIII(22):1933-1936. doi:10.1001/jama.1914.02570220043013