Professor Jaffa, too, of the University of California, has been doing most valuable service in testing the usefulness of fruits and nuts as human foods. He generously furnished the author with elaborate tables of his results, covering several years of observation, showing low nitrogen possibilities similar to those demonstrated by the writer and his colleagues at Cambridge and Yale. These have since been published, and relating to special kinds of foods, as they do, suggest a wide range of choice among the fruits of earth; but the collected evidence of this book shows that human nutrition is best served when the appetite, being kept at normal, is allowed to make selection from the whole range of nutritious products furnished by good Mother Nature. DR. H. P. ARMSBY In the Oct. 16th, 1903, number of _Science_, also, is an interesting article by Dr. H. P. Armsby on the heat values and muscular energy values of different food elements and their isodynamic replacement of each other under various conditions.—HORACE FLETCHER.] Explanation of The A. B. C. Life Series THE ESSENTIALS AND SEQUENCE IN LIFE It would seem a considerable departure from the study of menticulture as advised in the author’s book, “Menticulture,” to jump at once to an investigation of the physiology and psychology of nutrition of the body and then over to the department of infant and child care and education as pursued in the _crêche_ and in the kindergarden; but as a matter of fact, if study of the causation of human disabilities and misfortunes is attempted at all, the quest leads naturally into all the departments of human interest, and first into these primary departments. The object of this statement is to link up the different publications of the writer into a chain of consistent suggestions intended to make life a more simple and agreeable problem than many of us too indifferent or otherwise inefficient and bad fellow-citizens make of it. It is not an altogether unselfish effort on the part of the author of the A. B. C. Life Series to publish his findings. In the consideration of his own mental and physical happiness it is impossible to leave out environment, and all the units of humanity who inhabit the world are part of his and of each other’s environment.