From Find A Grave:
Civil War CSA Senator, US Senator. After graduation from the Transylvania Law School in Lexington, Kentucky, Vest began a journey that he hoped would end in California. While delayed by a stage accident in Missouri, Vest undertook the defense of a young black accused of murder. After Vest secured the youth's acquittal, the young man was seized by a mob & burned at the stake. Threats against Vest made him determined to stay in Missouri. He had great success in his profession & in politics. By 1860 he was a presidential elector & a representative in the state legislature. A year later he chose to support the South & served with General Price as judge advocate general. He was soon elected a member of the Confederate Congress & served in both the regular Congresses of the Confederate States, including one year as senator. After the war Vest returned to private practice in Missouri & was elected to the United States Senate.
"Man's best friend is his Dog" (Excerpt from Wikipedia)
After the war he returned to Pettis County moving to Sedalia, Missouri, and resumed his law practice. It was at this time in 1869 that Vest was asked to represent Charles Burden and Old Drum in the case that would make him famous, Burden v. Hornsby.
Vest took the case tried on September 23, 1870, in which he represented a client whose hunting dog, a foxhound named Drum (or Old Drum), had been killed by a sheep farmer, Leonidas Hornsby. The farmer (Burden's brother-in-law) had previously announced his intentions to kill any dog found on his property; the dog's owner was suing for damages in the amount of $150 (equivalent to $3,033 in 2019), the maximum allowed by law.
"During the trial, Vest stated that he would "win the case or apologize to every dog in Missouri." Vest's closing argument to the jury made no reference to any of the testimony offered during the trial, and instead offered a eulogy of sorts. Vest's "Eulogy of the Dog" is one of the most enduring passages of purple prose in American courtroom history (only a partial transcript has survived):
Gentlemen of the jury: The best friend a man has in this world may turn against him and become his enemy. His son or daughter that he has reared with loving care may prove ungrateful. Those who are nearest and dearest to us, those whom we trust with our happiness and our good name, may become traitors to their faith. The money that a man has, he may lose. It flies away from him, perhaps when he needs it the most. A man's reputation may be sacrificed in a moment of ill-considered action. The people who are prone to fall on their knees to do us honor when success is with us may be the first to throw the stone of malice when failure settles its cloud upon our heads. The one absolutely unselfish friend that a man can have in this selfish world, the one that never deserts him and the one that never proves ungrateful or treacherous is his dog.
Gentlemen of the jury: A man's dog stands by him in prosperity and in poverty, in health and in sickness. He will sleep on the cold ground, where the wintry winds blow and the snow drives fiercely, if only he may be near his master's side. He will kiss the hand that has no food to offer, he will lick the wounds and sores that come in encounters with the roughness of the world. He guards the sleep of his pauper master as if he were a prince. When all other friends desert, he remains. When riches take wings and reputation falls to pieces, he is as constant in his love as the sun in its journey through the heavens.
If fortune drives the master forth an outcast in the world, friendless and homeless, the faithful dog asks no higher privilege than that of accompanying him to guard against danger, to fight against his enemies, and when the last scene of all comes, and death takes the master in its embrace and his body is laid away in the cold ground, no matter if all other friends pursue their way, there by his graveside will the noble dog be found, his head between his paws, his eyes sad but open in alert watchfulness, faithful and true even to death.
Vest won the case (the jury awarded $50 to the dog's owner) and also won its appeal to the Missouri Supreme Court. A bust of the dog resides in the Missouri Supreme Court building in Jefferson City, Missouri. In 1958, a statue of the dog was erected on the Johnson County Courthouse lawn containing a summation of Vest’s closing speech, “A man’s best friend is his dog.”