{HEAD ~ A laser beam} is focussed on to {TAIL ~ a capillary} by means of a lens, mirror and beam splitter system and measurement of the velocity of the blood cells in a direction substantially perpendicular to the surface of the tissue is effected by detecting directly back scattered radiation 
is focussed on to
{ HEAD ~ A laser beam } is focussed on to { TAIL ~ a capillary } by means of a lens , mirror and beam splitter system and measurement of the velocity of the blood cells in a direction substantially perpendicular to the surface of the tissue is effected by detecting directly back scattered radiation
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH