This unusual device was made in the University glassblowing workshops around 1970 when Addenbrooke's routine laboratories were still a department of Cambridge University. It was used to study samples from patients in whom an inherited disorder of their haemoglobin molecule causes as abnormality in the way their blood carries oxygen round the body, both as an aid to diagnosis and to further research in this sort of problem. Containing a solution of a minute amount of the patient's blood, the device was monitored and a graph was built up from the spectrophotometric colour changes, while the gas in the cuvette was being gradually changed fro a vacuum (this is, no oxygen) to pure (100%) oxygen. The shape of the graphical curve reflects the chemistry involved as particular varieties of haemoglobin pick up oxygen molecules in the patient's lung, and release them to the body tissues.