Biopsy tissue storage. Tissue samples (biopsies, pink) inside sample holders, ready to be frozen by immersion in liquid nitrogen. They are covered in a liquid that will freeze around the tissue sample and preserve it for future examination. A pair of forceps is being used to pick up one of the tissue sample holders. Examination of the biopsies will help diagnose the exact nature of the patient's condition. These biopsies have been obtained from the knee of a patient with rheumatoid arthritis. These biopsies were obtained by an arthroscope, a type of endoscope that is used to look inside joints. Photographed in the UK.