▁that ▁field . ▁ ▁While ▁Dra per ▁thought ▁this ▁a ▁tra ged y ▁at ▁the ▁time , ▁he ▁later ▁looked ▁at ▁it ▁as ▁a ▁great ▁turning ▁point ▁in ▁his ▁career , ▁free ing ▁him ▁for ▁work ▁that ▁would ▁eventually ▁bring ▁him ▁prom in ence ▁in ▁his ▁profession . ▁ ▁Dra per ▁was ▁allowed ▁to ▁finish ▁the ▁course , ▁after ▁which ▁one ▁of ▁his ▁older ▁class m ates , ▁Dr . ▁Hugh ▁C um ming , ▁was ▁put ▁in ▁charge ▁of ▁a ▁scientific ▁study ▁of ▁shell fish ▁and ▁water ▁poll ution . ▁ ▁C um ming ▁then ▁put ▁Dra per ▁in ▁charge ▁of ▁a ▁small ▁labor atory ▁in ▁Col onial ▁Beach , ▁Virginia ▁where ▁he ▁spent ▁the ▁next ▁year ▁studying ▁the ▁b acter i ological ▁cont am ination ▁of ▁o yst ers ▁in ▁the ▁Pot om ac ▁River . ▁ ▁Since ▁both ▁Washington ▁D . C . ▁and ▁Alexand ria , ▁Virginia ▁dump ed ▁their ▁raw ▁se w age ▁into ▁the ▁river , ▁Dra per ▁was ▁to ▁answer ▁the ▁question ▁of ▁whether ▁o yst ers ▁were ▁affected ▁ 6 8 ▁miles ▁down stream . ▁ ▁He ▁discovered ▁that ▁the ▁poll ution ▁had ▁been ▁neutral ized ▁by ▁natural ▁processes ▁much ▁further ▁up stream , ▁and ▁thus ▁had ▁no ▁effect ▁where ▁he ▁ran ▁most ▁of ▁his ▁tests . ▁ ▁The ▁study ▁was ▁important ▁to ▁ease ▁fear s ▁that ▁poll ution ▁might ▁be ▁affect ing ▁the ▁extensive ▁o yst er ▁b eds ▁near ▁Point ▁Look out , ▁Maryland , ▁much ▁further ▁down stream . ▁ ▁Following ▁his