Document bBZGR34O3Jq3p444vpeEN0YZ0

J a n u a r y 1 J , 191+1 D r, E . Cowles A ndrus The. Jo h n s H opkins H o s p ita l B altim o re, M aryland Dear D oetor A ndrus: I am v e r y g l a d t o se n d you,under se p a ra te c o v e r, s e v e ra l r e p r in ts w hich give most of the accum ulated c lin ic a l and e x p e ri m ental o b se rv atio n s on th e b eh av io r o f te tr a e th y l l e a d , W' h a v e a c o n s i d e r a b l e am ount o f d a t a w h ic h have not been p u b lish e d , b u t w hich have been a w a it in g th e day when I co u ld ta k e th e tim e to stu d y them p r o p e r ly and p u t them i n t o p r i n t . G e n e ra lly speaking, they v e rify the p re v io u sly p u b lish ed m a te ria l. There i s one e x c e p tio n , how ever, to w hich I w ish to c a l l your a tte n tio n , sin c e i t i s o f co n sid erab le c lin ic a l im portance in r e la tio n to the p o s s ib ility o f seq u elae, I h ith e rto c a lle d a tte n tio n to the f a c t th a t th e le a d con c e n tra tio n in th e b ra in tended to rem ain c o n sta n t, or n e a rly so , re g a rd le s s o f the la p s e of tim e a f te r th e c e s s a tio n o f e x p o s u re . More r e c e n t o b s e rv a tio n s have shown t h a t t h i s i s n o t th e c a s e a t a l l f o r some of thp o th e r o rg an ic lea d compounds, and th a t i t is p ro b a b ly n o t th e case f o r t e t r a e t h y l le a d . I t would appear th a t the e a r l i e r h ig h r e s u l t s were due to th e u se o f a m ethod o f a n a ly s is w hich i s much le s s s e n s i tiv e and a c c u ra te th a n th e p re s e n t m ethods . M any,-in f a c t m ost o f th e r e s u l t s on th e sm all b ra in s o f r a b b its were ju s t a t the lim its o f e rro r o f th e m ethod and w e re, th e r e f o r e , g r e a t ly m a g n ifie d when c a lc u la te d on th e b a s is o f 100 grams o f f r e s h m a te r ia l. You w i l l f i n d v e ry l i t t l e ad eq u ate in fo rm a tio n on th e p a th o lo g y o f te tr a e th y l lead p oisoning, n o t because the m atter has not been stu d ied , but because very l i t t l e of consequence has been fo u n d . The b r a in s o f a c u te ly p o iso n e d an im als alw ays show c o n s id e ra b le edema and som etim es a con s id e ra b le amount o f hyperem ia or c o n g e stio n . M icro sc o p ic ch an g es, w hich a re a s s o c ia te d w ith edema and lo c a liz e d le s io n s , have n o t been found. M oreover KE 001S780 n* - 2- f a t a l c a se s in human b e in g s have ad d ed v e ry l i t t l e more to th e p ic tu re * In t h i s c o n n ec tio n i t is in te r e s tin g to c o n sid e r th a t o f th e c ase s which have s u rv iv e d , o f which th e re h as been a goodly num ber, l i t t l e o r n o th in g i n th e way o f s e q u e la e has been seen* S ev eral su rv iv o rs have had m ental d istu rb a n c e s, and In one In sta n ce th ese continued f o r su c h a p e r i o d t h a t we f e a r e d t h e y w ould be perm anent. Lead an aly ses c a rrie d o ut during th is p e rio d , how ever, showed th a t th e le a d c o n te n t o f th e tis s u e s rem ain ed h ig h , and i t was n o t u n t i l s u b s ta n tia lly norm al c o n c e n tra tio n s in the blood and u rin e w ere re a c h e d , t h a t the symptoms s u b s id e d . I f any sp e c ific q uestions sh o u ld su g g e st them selves to you from th e exam ina t i o n o f t h e s e a r t i c l e s , I s h o u ld be g la d t o do my b e s t to answer them . r e g a r d s , I am W ith kindest p e rs o n a l S incerely yours, HAK^Is R o b e rt A. K ehoe, M.D. P .S . I am s e n d in g you a few o t h e r r e p r i n t s w hich may b e o f I n t e r e s t to y o u . RAK. 0019781