Document YjKpgQyVdp9vVxM18EvKwpXXV

;;fw-fV' il> >'?ijn J : -J?--T v .^ i j) - K-; ELS T O N L. B ELK N A P , M. D. 231 W. Wisc o n sin Av e. MILWAUKEE November 28, 1932 Dr. Robert Kehoe, Laboratory of Applied Physiology, College of Medicine, General Hospital, University of Cincinnati, Cincinnati , Ohio. _ My dear Dr. Kehoe: I surely appreciate the reprints that you have sent me as well as your letter of November 22. Our technician states that by the Lederer method she means the method referred to on Page 167 of Todd's Clinical Diagnosis by Laboratory Methods - 6th Edition. In this method she evaporates 500 cc. of a 24-hour specimen ad ding sulphuric acid and potassium persulphate for destruction of organic matter. She then adds 50% alcohol in equal amount letting it stand overnight getting the lead sulphate. She then filters through a Buchner filter and washes the precipi^tate with 95% alcohol td*;remove the color. She then dissolves the precipitate with a small amount of water and adds sodium acetate,: and filters again to clear the solution. She now makes this solution; of lead acetate up to a known volume. She takes 10 cc.. of this and divides it so that she can use one-half as a check. She passes hydrogen sulphide through this and compares the precipitate of lead sulphide with a known concentration of lead acetate which has had the hydrogen sulphide passed through it. Her lowest dilution of these standards is that of .009 mgm. I have no doubt that your methods are much more accurate but I would be pleased to have your opinion upon this particular method. \/ \: I VI \{ '/ t ""A ' I am wondering if it would be possible for our technician to spend a few days or a week or more in your laboratory to familiarize herself with this technique as well as possibly even to become familiar with the technique of analyzed foods for lead. If we are to do any accurate work in our hospital in examining urines for lead, it is apparent from your studies that we must know exactly the amount of lead con tained in the food ingested. I am looking forward myself to a visit to your laboratory some time within the ensuing year. 0019890 I am Sincerely yours, N20045