In a recent publication1 we had the privilege of considering at some length the question of the activation of the pancreas by secretin, with especial reference to malnutrition and diabetes. In it we pointed out, among other things, that in some animals, especially those which are carnivorous and are not provided with grinding molar teeth, in which animals there must, therefore, be either a large amount of acid gastric secretion or a high degree of acidity within the stomach, there was evidence that pro-secretin is present in the intestines in quantities larger than are found in human beings. We also reached the conclusion that the evidence to date for the absence or deficiency of pro-secretin as the cause of some cases of diabetes and malnutrition was insufficient. These were our main findings as far as the present communication is concerned, but the experience gained in these connections led us to