Document nq4ZD517jJ894jpjemwZ3xam

PEASE LABORATORIES, INC. BIOLOGICAL,CHEMICAL AND SANITARY INVESTIGATIONS 3 9 --4I WEST 38TM STREET NEW YORK ; ESTABLISHED 1904 June 21 19 4-0 Dri. Robert A. Kehoe Kettering Laboratory of Applied Physiology College of Medicine Cincinnati, Ohio :ear Eoctor Kehoe: Thanks v er y much indeed for your letter of the 13th and for your kindness in loaning me the copy of your very excellent . nrlesentation of such a fundamental series ox investigations on the effects of ingestion of lead, and the relation of the same to other avenues of access of lead to the body tissues. I have taken the liberty of having the text and bibliogra phy of your paper copied and will, of course, observe carefully thje suggestion that it be considered confidential until such time asi the paper actually appears in published form. The data, how ever, will be of very considerable assistance to us if, in the meantime, E'r. Calvery should take up for active discussion the results of our researches upon the penetration of the skin by j_ead compounds which undergo chemical alterations in contact with the hair colorations very probably associated with reactions be- tween the lead aid certain constituent factors of the hairs. As yet we have found no evidence that the lead penetrates beyond the surface layers of the epidermis, or if it does gain access to the actual layers of the skin the lead is not taken up by the lymphatics, for our analysis of the lymph glands tends to show no! increase in the amounts of lead in those that drain the areas trleated. . In your article you refer to the outward passage of the lead with the perspiration, which is indeed very interesting. In the case of the rabbits which we have been using as experimental anjimals, we are dealing .with, skins in which there is at least the Eipnimumof perspiration. Rabbit skin is substantially devoid of sweat glands, or, at least, they are very few in number. On the other hand, we know they have very large numbers of sebaceous gjjands, and it is true that the rabbits subjected*-to*-treatment with a lead compound on the skin appear to have very substantial A |r. Hebert A. Kehoe 2 '/kl/4-0 amounts of lead in the non-treated areas of the skin, in both the skin itself ahe. in the fur. It has been shown- in researches tpiat even when lead was- ingested, the very substantial 'amounts of Ijead found in the fur and in the skin were due to external contaiainlation rather than to outward penetration from the tissues to which tjhe lead was undoubtedly carried by the blood circulation. On the other hand, fromyour investigations the leadywouid certainly be present in the feces iii very substantial amounts, and under ordinary conditions of housing the fur and skin of the rabbits might very readily become contaminated by contact with the fecal material. .Also, your results on the amounts of lead present in tne urine indicate that there would be an opportunity for rabbit fpr ana skin to become contaminated with lead from that source. In any case, there appears to be no doubt that the fur and tie external surfaces of the skin of the rabbit become laden with considerable lead: whenever the animals are fed lead -compounds, or the same are applied to restricted surfaces of the body. In oar rabbits we founa restricted amounts of lead in the internal organs and in the lymph glands, notwithstanding substantially greater anounis in the untreated skin and untreated fur. In the case of our animals they ell put on weight, so t-pat whatever absorption of lead took place failed to affect their irowth tendencies in any material manner. we did not do blood work on the animals, largely on the grounds that blood investIgationsof animals give results that are not very uniform even tinder the nest of metabolic and environmental states. Your blood work on the human being, where conditions could be considered reasonably standardized, tends to confirm our feelings with respect to this line of investigation on such a variable animal as the rabbit. : It is indeed very interesting that the results of so many of these tests tend to show the harmlessness of fairly sub stantial amounts of lead gaining access systemically. Of interest is the idea that up to certain concentrations the animal body can absorb, excrete and perhaps store in reasonably harmless Ideations considerable amounts of metals, and that no undue or pathological reactions take place until amounts of the metals egther gain access to the circulatory system by entrance or by rdason of excessive release for exit, in concentrations veil above those following this earlier apparently more or less normal course. In investigations we made years sgo on canned foods with resued to the storage of tin, ve found this fundamental feature to be true; namely, the various tissues of the bodies of \ .'if. Robert A. 'Kehoe 3 6/ 2 1/ 4 0 +l'e monkeys appeared to he capable of holding approximately the me amounts of tin, no matter howmuch was present in the food ich they consumed. In those investigations the skin of the imais retained very substantially more than s.ny other body oryen. is most of the tin was ultimately determined to be present in one of the food, ingredients with which the canned, glass packed, and esh vegetables -.ere mixed, the generally uniform final results iii ell the tests, regardess of either the sotiree or the amount of the food eaten, indicated that the animals have this capacity to take cure of approximately the same amount of the metal tin. Somewhat the same results have been obtained by ns and by Uouison working with oysters, and the copper commonly found iri oysters. Godson's work particularly indicates that up to a. certain point the individual tissues of the body rill store operoriaately the sane maximum-amounts of copper quite unaffected 'by -nything but very extraordinary amounts fed of certain types of copper, such as, copper sulphate. again thanking you for your kindness in making available to me the results of your very interesting work, and with very best ' 'ishes, Yours sincerely, T:/?ease VK Enclosure