The effect of nitrogen mustards on the viscosity of thymonucleate.

The nitrogen mustards used in these experiments were the hydrochlorides of ethyl bis (/3 chloroethyl) amine, methyl bis (/3 chloroethyl) amine, and tris (fl chloroethyI) amine. Sodium nucleate was prepared from calf thymus by a modification of Hammarsten's procedure (5). After the preliminary extraction, filtration, and addition of CaC12, a precipitate was obtained by bringing the final ethanol concentration to 15 per cent. The precipitate was kept in the refrigerator overnight, and separated by centrifuging and washed with 15 per cent ethanol. The washed precipitate was dissolved in a saturated NaC1 solution and allowed to stand in the refrigerator for 3 days. The solution was filtered through "Hyflo Super-Cel" under vacuum in a Buchner funnel. The sodium thymonucleate was precipitated by adding 95 per cent ethanol and was washed and redissolved in H20. It was reprecipitated and washed with ethanol and ether and dried in vacuo over P205. Despite the uniformity in procedure, the viscosity of the various batches of thymonucleate varied considerably. The viscosity measurements were made according to the method described by Bingham and Jackson (1). A pressure of 20 cm. H20 was used and the viscosimeter was kept in a constant temperature bath at 30 ~ C. No attempt was made to express the values in terms of absolute viscosity.