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Scientific Proceedings (132) 



moved, The filtrate from the NaCl precipitate contains no active 

 substance. The rapid method which, even with filtration over 

 night, can be carried to completion in 18 hours is as follows : 



1. Beef pancreas trimmed free of extraneous tissue at the 

 slaughter house is placed at once in 0.2 N HQ, chilled to 0° C, 

 and is transported to the laboratory in this condition. 



2. Upon arrival at the laboratory the acid is discarded, the 

 pancreas hashed in a meat grinder and a known weight mixed 

 immediately with 4 vols, fresh 0.2N HQ. 



3. The mixture is brought to 75° C. where it can be held for 

 one hour. Or it may be brought rapidly over a free flame just 

 to the boiling point. 



4. It is then chilled under the tap to 20° C. or lower to con- 

 geal the melted fat which is skimmed off. 



5. The material is strained through cheese cloth and neutral- 

 ized with N/1 NaOH to a P H of 4.9 or titration to phenolphtha- 

 lein to .01 N. It is then filtered through coarse filter paper 

 over night. 



6. To each 1,000 c.c. of filtrate 250 grams NaCl are added 

 and stirred to complete solution. Precipitation is rapid and 

 complete. The precipitate contains all the active substance to- 

 gether with some extraneous proteins. 



7. After standing for at least two hours the suspended 

 precipitate is decanted and either filtered or centrifuged off. 



8. In either case the precipitate is treated with alcohol of not 

 over 70 per cent, by volume and the insoluble proteins discarded. 



9. Three to five volumes of amyl alcohol are added and the 

 mixture thoroughly shaken and centrifuged. The precipitate is 

 found between the aqueous and alcoholic layers. 



10. The precipitate is treated with 80 per cent, alcohol, fil- 

 tered, and the filtrate evaporated to dryness by air currents. 

 Further purification is accomplished by re-solution in 80 per cent, 

 alcohol and evaporation in vacuo. 



11. The dry material is taken up in sterile water and filtered 

 aseptically, adjusting the reaction of P H of 4.0 or lower. 



12. This final product usually gives a very faint biuret re- 

 action. 



The final product is water clear and, because the final pre- 

 cipitate is very soluble in water, can be made as concentrated as 

 desired for administration. 



