(1) Of 71 cases of malignant growths the Shaw-Mackenzie test was positive in 49, doubtful in 5 and negative in 17. Epitheliomata of the skin all gave negative results, and some cases which had been treated with lead, X-rays or radium, and some cases of advanced inoperable carcinoma in old people also gave negatives.

(2) In 102 cases of various diseases other than growths (malignant or otherwise) negatives were obtained in 65 cases while 19 were doubtful and 18 were definitely positive. The chief conditions likely to give wrong "positives" are venereal disease, heart cases, nephritis, pulmonary tuberculosis, pregnancy and menstruation.

(3) Cloudy sera do not always clear on incubation with co-enzyme of pancreatic lipase, and unless such clearing takes place they should be discarded, as a high percentage of false positive results occurs in these instances.

(4) A 1 per cent, solution of cholin hydrochloride gave very similar results to the carcinoma extract.

I am deeply indebted to the following for supplying me with material, either serum or tumours, and without whose kind co-operation the work could not have been carried out: Dr Cooke, Addenbrooke's Hospital, Cambridge; Dr Varrier-Jones and Dr L. Stott, Papworth Hall, Cambridge; Dr L. King, Cancer Hospital, Fulham Road; Dr Piney, Charing Cross Hospital; Dr Perrin, Dr J. R. Marrack and Dr Sybil Robinson, London Hospital; Professor McIntosh, Middlesex Hospital; Professor F. R. Fraser and Professor G. E. Gask, St Bartholomew's Hospital; Dr Alport, St Mary's Hospital; Professor Maclean and Dr Osmond, St Thomas' Hospital; Professor Choyce, University College Hospital.

I also have to thank Professor Ellis, of the London Hospital, for kindly allowing me to work in the research laboratory on several occasions.