The devout worshippers at the feet of Hygeia may lament this inversion. But they need not despair. The world is not destined to go short of soap. Two British chemists, as a result of deep thinking, decided to attack the soap manufacturing issue _de novo_. They were not disposed to accept, at their face value, all that the textbooks set forth concerning the chemistry of soap. They were rather impressed by the fact that the manufacture of soap had undergone no fundamental change since the first cake was placed upon the market, which was during the days when Pepys was walking among us taking notes. So far as soap chemistry theories prevailed the two chemists in question were Bolshevic in their attitude towards them, which was a fortunate circumstance. A cake of soap is as familiar as a loaf of bread. Yet how little do we know about it, despite the brain-power which has been crowded upon its preparation. As a cleansing agent it is without a rival. Many big industries would have to close their mills to-morrow were their supplies of soap cut off. Yet its composition is very simple. It is composed of only two basic ingredients--fat, from which the glycerine has been extracted, and caustic soda. No matter how much you may pay for the article, be it a penny or half-a-crown a tablet, analyse it, and you will find that there is the soda which achieves the cleansing effect, and the fat which gives the lather. It is quite possible a variety of other substances may be found associated with the two basic constituents, such as diatomaceous earth, Fuller’s earth, farina, traces of disinfectant, colouring matter, cereal grains, perfume, and even water. But beyond rendering the soap attractive to the eye, pleasant to the nose, or to a certain degree germicidal, these additional materials perform no useful purpose. They are described as fillers, but in more candid language may be set down, for the most part, as sheer adulterants. Few articles lend themselves so readily to adulteration as soap. Was it not an analyst who, in the courts, described a piece of soap submitted to him for investigation as a striking example of water standing upright! Although we profess to know so much about soap and its properties, we are really labouring in ignorance. No chemist can tell you explicitly whether the cleansing action exercised is the result of chemical, physical, or mechanical action. It is one of those questions which the seeker after truth had better not press home too energetically, because the man of brains would probably retort firmly, but gently, that the interrogation involves such a complex reply as to be beyond your powers of comprehension.