Electrometric Serology *

Electrometric serology may be defined as serological study carried on by means of electrical measurements, of a physical chemical nature, made upon sera in any given state and referred to similar measurements made upon sera in a defined standard state. It is an attempt to introduce another exact method into a field already remarkably exact when the abstruse nature of the materials studied is considered. An effort has here been made to apply the methods and measuring devices used in physics and physical chemistry, coupled with reasoning based upon thermodynamical principles, to the study of serological changes in pathological states and of variations within physiological limits. The basic concept of ionic activity as defined by Lewis5 and worked out to a great extent by Harned, Lewis, and others, is used in explaining the theoretical background for the changes expected, and found. Those serological tests which have previously been highly developed and found very useful are of such a nature that either the concentration of one constituent is determined without regard to other possible changes which might occur, or a summation effect is measured, in which the observed change is the algebraic sum of all the changes. It is obvious that in many conditions in which an actual change had occurred such a shift could not be demonstrated by these methods, but such shortcomings, being inherent in the method, are inescapable. If, then, some function could be measured which might give an idea, not necessarily of totality or of specific concentration, but of the relations of what may be called the equilibrium of the various constituents and, at the same time, a function of the total concentration of the various constituents, it should be possible to develop a method of great value in revealing further interesting or significant information. Such a means of study is found lying at hand, merely awaiting proper development. It is only recently that our laboratory methods have become sufficiently refined to allow us to test accurately thermodynamical principles long known and mathematically proved. This is due to the extremely small allowable limit of error which was most diffi-