Best said possibly the only thing that would have changed my attitude: 'What will happen to me?' 'Your friend MacLeod will look after you,' I said. Best replied, 'If you get out, I get out.' There was silence for some moments. I thought of all the joy of the early experiments which we had known together. Here was loyalty.

Best and I worked in the sub-basement of the old medical building day and night. Time, meals, sleep - all were of secondary consideration. We had to get insulin into a form that was refined enough for continued clinical use.

Insulin is not a cure for diabetes; it is a treatment. It enables the diabetic to burn sufficient carbohydrates so that proteins and fats may be added to the diet in sufficient quantities to provide energy for the economic burdens of life.

If a patient became sugar-free and blood sugar normal on a basal requirement diet, the caloric intake was gradually increased until sugar appeared in the urine. The tolerance was thus ascertained.