Dr Pollock came in to talk to the boys about her research on vaccines and the lymphatic system, at the University of Oxford and Imperial College London. In her research, cells from lymph nodes are sampled using a technique called fine needle aspiration (FNA) which is a safe and well- tolerated procedure that involves taking cells and fluid from a lymph node using a needle. The boys enjoyed attempting to replicate some of her work by doing a mock ultrasound scan of lymph nodes. This involved finding grapes in tofu using an ultrasound scanner. On the scan the grapes looked like lymph nodes! To finish off the session, the boys were especially excited to watch a short clip of Dr Pollock appearing on Operation Ouch!