Allow the clams enough time to open their shells-this will be indicated by a burst of steam and popped-open shells, anywhere from 2â3 minutes to 5-10 minutes, depending on the type of clams. If some don't open in this time, discard them as they probably were already dead.
Spleen, lymph nodes, adenoids, tonsils are the encapsulated secondary lymphoid organs. Mucosa associated lymphoid tissue distributed throughout the body such as alimentary canal, respiratory and urinogenital tracts etc. are the diffused secondary lymphoid regions.
Primary lymphatic organs are where lymphocytes are formed and mature. There are two primary lymphatic organs: the red bone marrow and the thymus gland. The development of white blood cells (haemopoesis) was covered briefly in the section on blood. Both T-cell and B-cells are 'born' in the bone marrow.