That organs that have reached full maturity and differentiation are stable and fixed in cell type and organization is false. Our organs are constantly in active regression, degeneration, and progression, and it is difficult to separate pathological from physiological changes. The pancreas is particularly in constant regression and progression. Thus it is peculiarly unstable and the limit of normality in its variations cannot be determined. Senescence is accompanied by multiple degenerative changes in many other organs and tissues, and associated with these are various benign and malignant tumors that seem to result from degenerative changes. Thus Oertel’s idea of endless proliferation as a result of differentiation is not an idle speculation but rests upon an anatomical and experimental basis. A. S. Warthin[149] says that syphilitic cases are generally regarded as cured if the Wassermann reaction is negative but there are very many cases that this escapes. It is commoner than is supposed, the usual estimates being that from 5 per cent to 15 per cent of deaths are due to it, but this writer for America and Osler for Great Britain, place it at 30 per cent. “Syphilis is the leading infection and the chief cause of death, particularly in males between 40 and 60, and in the great majority of cases its symptoms are myocardial, vascular, renal, or hepatic, and this is often not recognized as a remote result.” The author has never seen a marked case of syphilis cured. Most die as a result of mild inflammatory processes of the viscera and blood vessels rather than from paresis or tabes. It is progressive and marks the individual as damaged goods. Even immunity is bought at a price. All the organs must be examined before it is pronounced certainly absent. It is a spirochete-carrier. It tends to become mild but at any time the partnership between the spirochete and the body may be disturbed and the tissues susceptible to the violence of the spirochete may be increased so that the disease again appears above the clinical horizon. Chronic myocarditis is the most common form of death.