Gout as an anaphylaxis, hay fever as an external expression of gout, what a vista of therapeutic possibilities is opened up by these simple experiments with pollen extracts and foods. The subject ramifies in every direction, touching the gouty form of Bright's disease, gouty heart disease, endocarditis and pericarditis, the popular "hardening of the arteries," which may prove after all not to be due to meat in all cases or alcohol in all cases but certain foods in certain cases, the increase in deaths from heart disease and kidney disease in the fifth decade of life. The correlation of these gouty problems with this work in the prevention and cure of hay fever anaphylaxis awaits a Lister or a Pasteur or a Koch who will have an eye to see and a patient industry to search and find. When you have established hay fever as anaphylaxis or lowered resistance to a specific proteid, you may be sure that the immunologist will seize the patient as his own, carry him off to the laboratory, and there attempt to raise his resistance or develop immunity to the attacking proteid by giving minute doses of the poison gradually increased. The success of this procedure will be related in the next chapter. CHAPTER XI _IMMUNIZING WITH POLLEN EXTRACT_ The idea of preventing disease and poisoning by preparing the body with minute doses of that poison, gradually increasing until the body is immune, is an ancient one. The practice is Ur-alt, as my favorite German history books say; for it has been found among savages and primitive peoples and is practised in a crude way by every boy who accustoms himself to that noxious weed, tobacco. Then, there are the Psylli, whom Lucan tells of, who were by heredity immune to snake poison and who could make the favored stranger immune by inoculating him with small doses (_Pharsalia_, Book ix); and old King Mithridates, of Pontus, who believed in preparedness and kept himself prepared for the attentions of his faithful subjects by taking small doses of poison every day, keeping himself immune should by any accident some poison slip into his porridge (_Pliny_, Book xxv). Old King Mithridates was a good immunologist. He knew the transient nature of immunity and kept the treatment up. He knew that, if he stopped taking the poison for a week or so, he would go into a state of anaphylaxis and the next dose would kill him; so he kept himself in a state of anti-anaphylaxis by not permitting too long a time to elapse between doses, after the most approved rules of modern immunology. That patient whom Goodale immunized against horse-asthma who objected to a treatment that had to be taken for the rest of her life, should learn of old King Mithridates the true practice of immunity.