In his efforts to support his practice by scientific evidence the vegetarian has taken advantage of two theories, neither of which is very suitable for his purpose. Both have originated in quite recent years, and in the first instance, at any rate, had nothing whatever to do with a fleshless diet.

The better known, which is technically called the purin-free diet, owes its inception to a medical man who suffered from violent headaches which could not be prevented by any amount of medication. Determined to uproot them, he began to exclude one article of diet after another from his daily menu, obtaining thereby increasing relief, until he ultimately evolved a highly ingenious and scientific system of dieting which has proved of immense value in the treatment of many disorders. The first offenders deleted from his fist were fish, flesh, fowl, tea, coffee, and cocoa, all of which he demonstrated contained a large percentage of uric acid or substances which formed uric acid in their passage through his body. For this reason he was hailed as a deliverer by the vegetarians, and they immediately announced that flesh foods were disease-producing solely on account of their content of uric acid.

Most unfortunately for them, however, further investigations proved that not only peas, beans, lentils, but peanuts, oatmeal, wholemeal bread, asparagus, mushrooms, and other substances likewise contained uric acid or material which in the body is capable of producing uric acid. Despite these further discoveries, however, to this day their chiefest objection to flesh foods is their content of uric acid, conveniently forgetting or else explaining away the fact that their most trusted fleshless foods are equally worthy of indictment. In condonation of this anomalous attitude they advance the statement that careful preparation enables them to deprive vegetable foods of their contained uric acid, whereas by no amount of forethought can the uric acid be expelled from flesh foods.

It is interesting, however, to note that meat-juices, beef-teas, and gravies contain the major proportion of the purins or uric-acid-forming substances in flesh foods, and every cook knows how easy it is to separate them from the solid substance. This is, however, a work of supererogation, because Pavlow the eminent scientist has proved that these very meat-juices are the most digestion-compelling substances in existence. Hence the value of a few mouthfuls of good soup at the beginning of a meal.

From the uric-acid point of view, therefore, the average vegetarian is precisely in the same position as the average mixed feeder. I believe it is quite impossible to discover a perfectly purin-free diet, although it is doubtless easy to construct a daily menu comparatively free from substances likely to manufacture uric acid in the body. I am quite convinced that the uric-acid craze has been overdone. One can hardly open a daily newspaper without finding in its advertisement sheets reference to one or more medicaments calculated to expel all the uric acid from the body. Now apart from the fact that there is only one disease, viz. gout, the origin of which is known to be associated with uric acid, and in which it is judicious to use with extreme caution such substances as sweetbreads, kidneys, and liver, which contain an excess of that substance, uric acid to the extent of twelve or more grains is daily manufactured by the living tissues of every human being. It is conceivable that if this quantity is all that any individual can excrete in one day, the addition of any in the food would be dangerous, and in all probability there may be some susceptible individuals for whom this proposition is true.

But it has been proved that the average man is abundantly capable of clearing out of his body not only all the uric acid he manufactures himself, but all he introduces in his food, and there is not a single iota of evidence to inculpate uric acid as the originator of all diseases. At the same time, I must frankly admit that the origin of disease is in some way associated with toxins or poisons which we have been unable to excrete and which we are unable to isolate. I am quite sure, however, that any individual who can excrete all the poisons elaborated by the daily work of his tissues can with impunity swallow any average quantity of uric acid or food containing it.