Abstract
The ability of extracts of rabies-infected suckling mouse brains, freed from virus by centrifugation, to fix complement in the presence of mouse antirabies serum was confirmed. The complement-fixing (CF) activity, which was unstable, was partially purified by precipitation, solvent treatment, adsorption, chromatography and electrophoresis. There appeared to be constituents of normal brain which closely resembled the CF activity in their behaviour towards these treatments. Descriptions are given: of (a) a device for step-wise elution of chromatograph columns; (b) modifications to the LKB Produkter electrophoresis apparatus to ensure constant electrical resistance; (c) a method for estimating "protein" which is useful when the ultra-voilet (u.v.) radiation method is inapplicable.