This is a reference to a particular style of carriage, which usually had two seats facing forward and was drawn by two horses. In this case, it is said to have been ridden in by Dr. Century and is also described as being “old-fashioned,” which matches the characterization of Dr. Century himself. The OED cites “phaeton” as being used in English as early as 1735 to refer to this type of carriage. However, the word comes from the name of the son of Helios (the Sun god), Phaethon, in Greek mythology. One day Phaethon asked his father if he could drive his chariot, which led the sun on its path across the sky. Helios was convinced to let him attempt this feat, but Phaethon was too weak to hold the horses’ reins and the chariot careened out of control, almost striking the Earth and nearly setting it on fire. Zeus was so outraged that he killed the boy.
Dictionary of Greek and Roman Biography and Mythology Ed. William Smith. Little and Brown. Boston: 1849.
This is a phrase which Trollope uses to describe Dr. Fillgrave while the squire, Mr. Gresham, is conversing with him. Mr. Gresham has just proposed that Dr. Fillgrave meet Dr. Thorne and confer with him about the best medical approach which they should take with Lady Arabella. Dr. Fillgrave is an obstinate man and completely refuses to associate himself with Dr. Thorne as a result of a previous dispute between the two men. It is interesting that Dr. Fillgrave is referred to as a “Little Galen,” while his sometimes adversary Dr. Thorne was earlier depicted as the “Galen of Greshamsbury” (see the glosses in the commentary for Chapter 2 and Chapter 24). Galen was a physician and philosopher in the Roman empire and one of the most important medical doctors of his time; it is from his writings that we have much of our understanding of earlier medical practices. [MD 2005]