The purely chemical theory of gout and diabetes, that they are diseases of suboxidation--a theory most ably advocated by Bence Jones[2]--has {113} much to commend it from the valuable suggestions which it affords in the clinical management of these maladies; but it must be acknowledged that while a defective oxidation seems to be an essential factor in the production of gout and diabetes, it is impossible to reduce the process to the simplicity of a chemical equation. It cannot be claimed that the complex chain of transformations which organic chemistry has demonstrated in the destructive metamorphosis of albumen and starch in the laboratory is represented in the vital chemistry of the body. All that can be said in the present state of knowledge is, that the metabolism of food is in its nature a chemical analysis, modified and regulated by vital force, and resulting in the building up of tissues and in the conversion of potential into active energy. Imperfect blood-elaboration must depend upon much besides a disturbance of the balance between the amount of food ingested and the oxygen inhaled, though this must unquestionably be an important factor in its production. Heredity and the mysterious influence of the nervous system complicate the problem of the malnutrition which leads to gout, in such a way that while the general proposition may be maintained that gout is a disease in which suboxidation occurs, it is not possible to affirm whether suboxidation is the essence of the disease or only one of its phenomena. [Footnote 2: _Lectures on Some of the Applications of Chemistry and Mechanics to Pathology and Therapeutics_, H. Bence Jones, London, 1867.] It is probable, however, that the pathogenesis of the gouty dyscrasia involves a much more complex process than the simple accumulation of uric acid salts in the blood. Uric acid, like urea, is one of the normal results of the metamorphosis of the albuminous foods and tissues. In birds and reptiles it takes the place of urea as the final issue of this metabolism. It has been supposed, as one atom of uric acid can be split by oxidation into two atoms of urea and one of mesoxalic acid, that uric acid was the penultimate of urea, the result of a lower degree of oxidation. It is by no means certain, however, that it is a necessary antecedent of urea. In birds, who consume by their rapid breathing an enormous proportion of oxygen, as well as in the slow-breathing reptilia, the nitrogenous excrements are in the form of urates; and under such divergent conditions it is impossible to explain the variations in the proteid metabolism by varying degrees of oxidation. The only reason that can be assigned for the elimination of the nitrogenous waste in some animals in the form of urea and in others in that of urates is the teleological one that the urea is destined for a fluid and the urates for a solid excretion.