1.   The fluid contains various vitamins, minerals, sugars and proteins and it is the protein that sometimes gels to form lumps.

2.   The fluid contains some fetal cells, which can be drawn out in the process called amniocentesis and analyzed to find out whether the fetus has some genetic diseases.

3.   The fluid could contain nitrogen gas or salt water, or even an antibiotic for fish with hook wounds.

4.   The researchers bathed the vein grafts for about five minutes in a fluid containing the decoy DNA, using pressure to force the fluid into the vein walls.

5.   Such fluids contain no salt, which is essential to the body but conducts electricity.