cases of tuberculosis, of paralysis, or of dementia præcox, &c., without carefully considering the clinical aspect of each of them. Above all, one ought to make a continuous study of certain types of disease in their different stages. Thus, for instance, epilepsy ought to be observed before, during and after its onset, at the period of remission, and so on.
The normal individual also offers opportunities for such studies, on such occasions as the advent of puberty, the climacterium, &c.
All the various forms of nephritis supply another important field of research. Does the kidney play an active part in individual cases, or does it only excrete albumen that is out of harmony with the blood plasma—that is, does it, in the main, play only a passive part? The following observation illustrates a case of this kind. Serum, from a female patient suffering from nephritis gravidarum, decomposed placenta-albumen and placenta-peptone with great difficulty. The rotation of the serum was unusually high. When this serum was mixed with that of a normal pregnant patient, a change was observed in the rotation of the mixture; and the fact that this was due to a decomposition was proved by the dialysation method. Neither serum, dialysed by itself, showed any decomposites of albumen. When both sera—the one from the case of nephritis gravidarum, and the other from the normal pregnant person—were subjected
