In a previous page it has been stated that nowhere in the Roman classics does there exist any distinct allusion to physicians or surgeons as forming a regular part of the staff of the Roman army. There are several references, however, in ancient medical and classical authors to the fact of medical men being placed in professional attendance upon Roman Senators,[416] Consuls,[417] and Emperors during the course of their military campaigns. Thus Galen tells us that he himself was summoned in this last capacity to attend upon the Emperors M. Aurelius and L. Verus at Apuleia during their proposed campaign against some of the German tribes.[418] Various fragmentary notices exist regarding the physicians who attended upon those Roman Emperors who visited Britain. A medical author (whom Galen often quotes), Scribonius Largus, has left a valued therapeutical work, _De Compositione Medicamentorum_. This work was written, as we are informed in the preface to it, when the author was absent from Rome, and deprived of the greater part of his library. In his _History of Medicine_, Sprengel states, but I know not on what precise authority, that the work in question was composed by Largus when he was absent with the Emperor Claudius during his short campaign into England.[419] Our countryman, Sir Thomas Browne, makes a similar statement. In his _Hydriotaphia_, when discoursing on the want of Roman notices regarding the state, habits, etc., of the ancient Britons, he observes, “We much deplore the loss of that letter which Cicero expected or received from his brother Quintus, as a resolution of British customs; or the accounts which might have been made by Scribonius Largus, the physician accompanying the Emperor Claudius, who might have discovered that frugal bit of the old Britons (mentioned by Dion) which, in the bigness of a bean, could satisfy their hunger.”[420]