Chemistry plays an ever-increasing r\l=o^\lein the practice of medicine ; in the field of metabolism it is the alpha and omega. Medical chemistry deals largely with studies of body fluids and gases. The urine, because of its accessibility, was the first to be subjected to investigation, while the cerebrospinal fluid, because of its inaccessibility, has received relatively little attention to date. Although chemical changes undoubtedly do accompany infectious and protozoal diseases, the paucity of information concerning the nature of chemical changes in infections, and the complex nature of the proteins themselves, have barred, to a large extent, direct chemical approach to the study of infection. As a result, progress has come along other and indirect lines, namely, through the development of immunology. Because of the frequent involvement of the central nervous system in syphilis, and because of the relatively simple chemical character of cerebrospinal fluid, it would appear probable that chemical studies of this fluid in syphilis would yield facts of diagnostic significance. To date the chemical studies resulting in information of clinical significance have been largely relating to the globulin content and to substances affecting the colloidal gold curve. Since the cerebrospinal fluid ultimately is derived from blood, it is important to determine the mechanism of its production, that is, whether by filtration or active secretion. In any event, it is certain that marked changes in the content of the blood are reflected to a greater or lesser degree in the cerebrospinal fluid. On the other hand, it is apparent that diseases of the structures concerned in the formation and fate of the cerebrospinal fluid may bring about changes in its chemical constitu¬ tion and a disturbance in normal chemical relationship of the blood and cerebrospinal fluid. It would seem not unlikely that various diseases with predilection for certain structures and regions of the central nervous system should show more or less characteristic disturbances in the normal relationship of these fluids.
