private void getCovalentlyConnectedBitSet(Atom atom, BitSet bs, BitSet bsToTest) {
		int atomIndex = atom.atomIndex;
		if (!bsToTest.get(atomIndex))
			return;
		bsToTest.clear(atomIndex);
		bs.set(atomIndex);
		if (atom.bonds == null)
			return;
		for (int i = atom.bonds.length; --i >= 0;) {
			Bond bond = atom.bonds[i];
			if ((bond.order & JmolConstants.BOND_HYDROGEN_MASK) != 0)
				continue;
			if (bond.atom1 == atom) {
				getCovalentlyConnectedBitSet(bond.atom2, bs, bsToTest);
			}
			else {
				getCovalentlyConnectedBitSet(bond.atom1, bs, bsToTest);
			}
		}
	}