From the biological, and especially medical,
point of view no class of substances has in recent
years grown so rapidly in importance as the lipoide.
The purely chemical investigation of these substances
has been carried on by numerous observers since the
middle of last Century, but it is only during the last
twenty years, and especially the last ten, that any
great progress has been made. At the present day we
know thoroughly the constitution of several important
lipoide and we are able, in a general way, to make a reasonable classification of those which are less well
Mayer and Overton's theory of narcosis, the explanation of the pharmacology of many drugs, and the
numerous physiological theories dependant upon the
physics of a cell membrane have all helped to increase
the importance of a thorough knowledge of the lipoide
in physiology, and have stimulated numerous researches,
but the role played by these substances in pathological processes remains almost uninvestigated.