The raw material for the production of coal-tar products we have in abundance if we will only take the trouble to save it. In 1914 the crude light oil collected from the coke-ovens would have produced only about 4,500,000 gallons of benzol and 1,500,000 gallons of toluol, but in 1917 this output was raised to 40,200,000 gallons of benzol and 10,200,000 of toluol. The toluol was used mostly in the manufacture of trinitrotoluol for use in Europe. When the war broke out in 1914 it shut off our supply of phenol (carbolic acid) for which we were dependent upon foreign sources. This threatened not only to afflict us with headaches by depriving us of aspirin but also to removed the consolation of music, for phenol is used in making phonographic records. Mr. Edison with his accustomed energy put up a factory within a few weeks for the manufacture of synthetic phenol. When we entered the war the need for phenol became yet more imperative, for it was needed to make picric acid for filling bombs. This demand was met, and in 1917 there were fifteen new plants turning out 64,146,499 pounds of phenol valued at $23,719,805. Some of the coal-tar products, as we see, serve many purposes. For instance, picric acid appears in three places in this book. It is a high explosive. It is a powerful and permanent yellow dye as any one who has touched it knows. Thirdly it is used as an antiseptic to cover burned skin. Other coal-tar dyes are used for the same purpose, "malachite green," "brilliant green," "crystal violet," "ethyl violet" and "Victoria blue," so a patient in a military hospital is decorated like an Easter egg. During the last five years surgeons have unfortunately had unprecedented opportunities for the study of wounds and fortunately they have been unprecedentedly successful in finding improved methods of treating them. In former wars a serious wound meant usually death or amputation. Now nearly ninety per cent. of the wounded are able to continue in the service. The reason for this improvement is that medicines are now being made to order instead of being gathered "from China to Peru." The old herb doctor picked up any strange plant that he could find and tried it on any sick man that would let him. This empirical method, though hard on the patients, resulted in the course of five thousand years in the discovery of a number of useful remedies. But the modern medicine man when he knows the cause of the disease is usually able to devise ways of counteracting it directly. For instance, he knows, thanks to Pasteur and Metchnikoff, that the cause of wound infection is the bacterial enemies of man which swarm by the million into any breach in his protective armor, the skin. Now when a breach is made in a line of intrenchments the defenders rush troops to the threatened spot for two purposes, constructive and destructive, engineers and warriors, the former to build up the rampart with sandbags, the latter to kill the enemy. So when the human body is