of ph 7 8 for five hours at 4 u00b0 c the protein is gelled by dialysis against a solution containing 500 mm calcium chloride solution and 0 1 mm ammonium acetate buffer at ph 7 8 for one hour at 4 u00b0 c sodium azide can be added to the dialysant to a final concentration of 0 001 mm to prevent bacterial growth the resulting gel can be stored at 4 u00b0 c for at least four weeks the resulting gel can be converted back to a sol by dialysis against distilled water or aqueous 100 mm ethylene diamine tetracetic acid solution prior to extrusion or otherwise forming the object demonstration that fibroin is stored as a gel prior to spinning in a bombyx mori silkworm the state of the fibroin in the posterior middle and posterior part glandular of the anterior division of silk gland of the bombyx mori silkworm was assessed by dissection under a binocular microscope at different stages in the silkworm 39 s development glands rapidly removed from silkworms were transferred to silkworm ringer solution ph 7 8 for observation the material in the lumen of the gland appears to be initially present as a sol at all stages up until the final instar a few days before cocoon spinning commences whereafter it is stored as a gel up to and during the initial stage of cocoon spinning by cutting the duct anterior part of the anterior division across and watching whether the fibroin dope would flow out it was demonstrated that the fibroin was present as a.