The use of -the X rays both for Diagnosis and Treatment has become so universal that I have thought it would be interesting to lay before you a case which proves the necessity of caution in the use of this agent. Before reading the history of this case, I would like to briefly point out the difference in the application of the rays for therapeutical and diagnostic purposes.

For the treatment of disease, the rays are applied with the definite purpose of destroying such tissues as are diseased, and limiting the spread of infection in the surrounding tissues. In such cases much longer exposures are legitimate and the object of the operator is to push the action of the rays as far as justifiable in order to effect cure. In diagnosis, no such heroic measures can ever be permitted. The operator is merely a photographer or demonstrator, using a dangerous agent on healthy tissues and may through ignorance or enthusiasm cause irreparable damage to the patient.

The case I record here is one of damage caused by the rays used for, diagnosis only, and the resulting misery and illness has impressed me immensely as a surgeon who uses the rays constantly for skiagraphy, with the need of greater caution in my own practice. I accompany this paper with wax models or records of the patient's wound taken at frequent intervals. I find this a very convenient method of keeping a faithful and permanent record of wounds and deformities.

To ensure accuracy, I take a plaster cast of the object and then re-cast it in wax. In this case the ulcer was so intensly painful that I could only secure the record by placing a piece of oiled tissue paper over the wound and tracing through this the size and shape of the injured area, and then transferring this to the melted wax. The matter of colouring the model was often very difficult. I have never seen such a variety of colours as I had to record. I do not accept as correct any record unless, when it is placed side by side with the patient's skin, I am satisfied that the appearance is a fair and truthful copy.

I have no doubt that most people who see these records will think the colouring to be more enthusiastic than truthful, but I can vouch for the accuracy of the colours, bizarre as they must appear to anyone who has not seen the original. Dr. Inglis, the Radiologist to Christchurch Hospital, has watched the case all through and has passed the models as correct.