The discovery of a form of collagen which can be extracted from fresh connective tissue in cold, neutral, and mildly aklaline media (1-5) has suggested that a fraction of the total collagen exists in a dispersed or loosely aggregated state in the extracellular, extrafibrillar matrix of the connective tissues. The process whereby a dispersion of collagen molecules (tropocollagen (6)) might be polymerized in the tissues was suggested by the observation that simple warming of the extract to physiological temperatures results in the precipitation of fibrils with the typical detailed fine structure of native collagen (4, 5).In addition to describing a new procedure for isolating and purifying the extracted collagen, this paper presents some results of an exploration of the properties of crude neutral salt extracts of fresh guinea pig corium as a base line for further studies on the role of the extracted components in the fibrogenesis of collagen and the physiology of connective tissues.
Mogerials and General ProcedureGuinea pigs of both sexes ranging in weight from 100 to 500 gin. were fed Purina rabbit chow pellets (containing antibiotics) supplemented with lettuce daily and 25 rag. of vitamin C three times weekly.The hair was removed with an electric clipper and the animals sacrificed by intxaperitoneal administration of nembutal followed by exanguination da intracardiac puncture. The skin of the trunk was removed, the epidermis and subcutaneous tissue dissected away and the corium ground in a hand driven meat grinder, the cutting edges of which were kept cold with