In this connection, the studies of POHL, as elaborated by CHITTENDEN, promise to shed a flood of light upon the vexed and complicated problem which involves the theory of nutrition. If digestive leucocytosis, as delineated by these authors, be true, and we have no reason to doubt their conclusions, then we have a satisfactory explanation of the value of proper food for the sick, to say nothing of the nutrition of those who ordinarily enjoy good health. The fact being admitted that white blood-corpuscles or leucocytes are more rapidly developed after the ingestion of food, it follows that this cellular activity was intended to accomplish or aid in accomplishing certain metabolic changes. And when to this fact we add the knowledge advanced by METSCHNIKOFF concerning the function of phagocytes, which are said to be modified white blood-corpuscles, together with the scientific demonstrations of VAUGHAN, that these cells produce through the activity of their nucleus an antiseptic substance, we have a complete scientific explanation of the need for suitable food stuffs, not only in illness of every description, but also as a precautionary measure against disease. It is time that the study of the class of cases under consideration should be placed on a scientific basis, in order that we may have some definite idea of the objects to be attained—and the method of attaining them—expressed in terms which may be comprehended by the merest tyro in therapeutics, and to this end the contributions of METSCHNIKOFF, POHL, CHITTENDEN and VAUGHAN must be accepted as valuable preliminary data. The next thing in order will be to make these scientific facts clinical facts by making them practical, and it is therefore necessary that others should take up the task in order that the work may be carried to a successful termination. _THE PRINCIPLE INVOLVED IN THE SUBCUTANEOUS USE OF BLOOD-SERUM._ An important revelation has been made to the medical profession in the form of a communication to the _Medical News_ (Jan. 13, 1894), by Dr. C. F. DARNALL, of Llano, Texas. According to the report, twins suffered from ptomain-poisoning, and one of them died. The surviving child was treated by the subcutaneous employment of a normal salt solution, but without apparent benefit. Later, this was followed by the use of two ounces of blood-serum drawn from the arm of the father, a healthy young man. To quote the words of the author, “The child was carefully watched, and reaction occurred in about six hours. Improvement gradually took place, and in six days, upon a diet of thin corn-meal gruel at first, later by fresh milk prepared, the child was well. It was placed at the mother’s breast at regular intervals, and at the time of writing, nearly nine weeks after the onset of the illness of the children, the lacteal secretion is fully established.”