=The “Periodicity of War.”=--The doctrine of “the periodicity of war” was presented at the Lake Mohonk Conference on International Arbitration in May-June, 1899, by General Alfred C. Barnes, with the introductory remark that “no one deprecates war more than the soldier who serves from a sense of duty.” The speaker said that “with all our privileges, and in spite of the elevated spirit that undeniably prevails among us, the original savage lurks in the hearts of men here as elsewhere.” In two hundred and twenty-five years we have had ten principal wars--five during the colonial period and five since our independence was undertaken. The average interval between wars has been about twenty years--“an extremely interesting periodicity, as it brings into the arena a new race of fighting young men. So it seems that for each fresh generation of our youth the temple gates of Janus have to be opened, that the furies there confined may rush forth and devastate the earth. It looks almost like the operation of a natural law.” General Barnes’s theory of the origin of the war that the United States is still engaged in is the simple one that we were “spoiling for a fight.” * * * * * =Expert Opinions respecting Food Preservatives.=--At a recent hearing before an English Official Committee on Preservatives and Coloring Matters in Food, the representative of an eminent firm of preservers said that preservatives were not very generally used with fruits and jams. His firm regarded them as quite unnecessary, but he would not say they ought to be prohibited if used in moderate quantity. Besides coloring matter in vegetables, the only article used by his firm for coloring was an extract of cochineal. Mr. John Tubb Thomas, a medical officer, told of children who were injured by milk containing boracic acid, and said that in his experiments upon himself about fifteen grains of that substance a day had upset his digestive organs and produced sickness, with diarrhœa and headache. The use of the acid, he said, should certainly be prohibited in new milk, which was so largely the food of invalids and infants. Dr. W. H. Corfield said he had found salicylic acid in the lighter wines and beers. It was a slightly acrid, irritating substance, which was used externally for the removal of corns and warts, and was a most undesirable article to put in food. Mr. Walter Collingwood Williams, a public analyst, had found salicylic acid in a number of temperance, non-alcoholic drinks. Dr. Kaye, a medical officer of health, showed that the number of infant deaths was increasing, while the general death rate was decreasing, and attributed the fact, partly at least, to the growing and excessive use of preservatives. * * * * *