public function removeSheetByIndex($pIndex = 0)
    {

        $numSheets = count($this->_workSheetCollection);

        if ($pIndex > $numSheets - 1) {
            throw new PHPExcel_Exception(
            	"You tried to remove a sheet by the out of bounds index: {$pIndex}. The actual number of sheets is {$numSheets}."
            );
        } else {
            array_splice($this->_workSheetCollection, $pIndex, 1);
        }
        // Adjust active sheet index if necessary
        if (($this->_activeSheetIndex >= $pIndex) &&
            ($pIndex > count($this->_workSheetCollection) - 1)) {
            --$this->_activeSheetIndex;
        }

    }