Document oeZ0ayj1xQEe9L5N4n296Rpr

N17466 ., Kay 2; 1946 v t\ ^ yt** ~ lf -;;4........... w .y.`r.. ; Dr. C. Ottolina, Municipal A Reducto, 64, Caracas# Venezuela. '/p# - K ** ; ~r "> V 1 i i ' , "i - I*-l *^' <'* .' :"'`l n`"'v- .t .f Dear Dr . Ottolina* I am very happy "t?b have heardfromyouagain and to know that , you are backat home. . u;-/ < I am certainly very glad to do anything ''jTean. for a friend and colleague of yours, and accordingly I am taking the first step by sending to you for Dr. Jioguera, a series of reprints descriptive of the analytical methods in use in this Laboratory. ,Incidentally these papers vill provide the evidence that' will; enablehim to see that the criticism of the method when properly carried out Is invalid. I am also indicating certain other references to the literature, among these perhaps the most significant one which criticizes the Dithizone method is that of Lawrence Fairhall. Unfortunately Fairhall*s comments are not without bias, and the method which he devised to take the place of the Dithizone method is almost too bizarre to be worthy of. discussion. It so happens that he was among the last of the series of workers in this field to attempt to make use of the Dithizone method, by reason of his personal prejudice, and therefore it took him some time to learn what others have learned by prior experience. It can now be said quite safely, that one of the sound modifications of the Dithizone method is the best that can be used for general investigative work in this field. I find it necessary to correct you at one point, for I assume that the mistake is yours rather than one of Dr. Uoguera. I refer here to your reference to blood serum. The lead in the blood is found mainly in the red blood corpuscles and only to the extent of 5$ or less of what is there can be found in the serum. Accordingly the whole blood should be analyzed rather than the serum, and this should be done without the addition of any anticoagulant, since there is too much likelihood that such anticoagulants generally available in hospitals and medical offices will contain appreciable quantities of lead. ,,0>. I should feel, that Dr. Hoguera would be wasting his time in large part in the examination of the blood of men at the mixing plants. Furthermore, he will be complicating his problem considerably for reasons that I shall attempt to explain* First, let me point out that these men are or should bd so completely protected as not to absorb significant quantities of lead. Our observations in this country have demonstrated that this is the case among our workmen at this job, and unless there is some serious defect in the procedure K 001353 & . Dr. C. Ottolina - (} - May 2, 1946 in Venezuela the same should he the case there. I believe that it is the same there* The complication that I speak of arises from the fact that the lead concentration in the blood following the absorption of tetraethyl lead# is quite different than with which would obtain if the.same quantity of inorganic lead were absorbed in the same time In other words the relationship between lead concentration in the blood and that in the urine is quite different When tetraethyl lead is being absorbed. For this reason Dr. Noguera will be starting with a difficult problem# when in my opinion# he should start with the simplest that he can find. For this reason I suggest that he attempt to stiAdy '^he blood and urinary lead concentrations of workmen engaged in some one of the more common lead trades. For example. If there are any lead burners In chemical plants# or solderers in other indus tries, or-men engaged in the manufacture of electric storage batteries he would-have a much better chance of finding what he is looking for. I should be very glad indeed to be of any assistance I can to Dr. Koguera for no other reason than that a serious medical Investigator la entitled to all the help his colleagues can give him. I think we should be able to point out many of the difficulties which we have had and thereby save him much time and unhappiness. Vith kindest personal regards# Sincerely yours, RAX ef Copy by air mail. Reprints under separate cover. Dictated but not read. Robert A. Kehoe# M. D. ! iyA- . ` ;A;J- A-AA :A . AApAiA;.A^ AAi. A-. .> 0013310