The work of Louis and of his pupils, W.W.Gerhard and others, revealed the distinction between typhus and typhoid fever, and so cleared up one of the most obscure problems in pathology.

By Morgagni's method of "anatomical thinking," Skoda in Vienna, Schonlein in Berlin, Graves and Stokes in Dublin, Marshall Hall, C.J.

B.Williams and many others introduced the new and exact methods of the French and created a new clinical medicine.

A very strong impetus was given by the researches of Virchow on cellular pathology, which removed the seats of disease from the tissues, as taught by Bichat, to the individual elements, the cells.

The introduction of the use of the microscope in clinical work widened greatly our powers of diagnosis, and we obtained thereby a very much clearer conception of the actual processes of disease.