The discovery of insulin made it necessary to publish a second edition of this book, the first appearing in 1922. Petrin uses the high fat and low protein diet, which is known as the Newburgh diet in this country. The good results are explained by Snapper's (Amsterdam) work on the secretory function of the kidney. By giving the kidney a rest from the secretion of nitrogen waste products, it is easier to take care of the beta oxidation of oxybuteric acid, diacetic acid and acetone. In this way, acidosis is prevented. Insulin, he believes, should be used only in coma and when the blood sugar does not come down to normal when the patient is on a maintenance diet.