For obvious reasons, the game of professional baseball is completely different than it was 20 years ago. Even more different 50 years ago and 60 or 70 years ago. Because of that, the thoughts of comparing players who played between 100 and 130 years ago leaves us no room for comparison. The best of this era will always be remembered for being the best of their time. The same could be said about the best players of the steroid era. Artificially enhanced or not, they still were the best of their generation. I think the same applies to the best pitchers of the 19th century.
John Clarkson pitched 12 seasons in the National League and managed to win 328 games for his career. He also pitched in a National League that would make it very difficult for the conventional baseball fan to know enough about the names of the teams in that time. The teams that Clarkson pitched for were the Worchester Ruby Legs, the Chicago White Stockings, the Boston Beaneaters and the Cleveland Spiders. After the 1899 season, only Chicago and Boston still had National League teams. Clarkson pitched in three Championship series, the 1885 and 1886 World Series for the White Stockings against the St Louis Browns; where they tied the first and lost the second and the 1892 Championship Series for the Spiders when they lost to the Beaneaters.
Charles "Old Hoss" Radbourn gets a lot of credit for his dominance of the latter part of the 19th century mound. In fact, his record of 59 wins in a season will never be duplicated in two seasons of the modern baseball era. Denny McLain came the closest when he won 31 games in 1968 and followed it up with a 24 win season in 1969.
In 1885, a man of just 17 MLB games prior to the season, John Clarkson made an incredible 70 starts out of the team's 112 games under manager Cap Anson. He won 53 games that season, topped only by Hoss' 59 the season before. Out of his 70 starts, he managed to complete 68 of them, throwing a total of 623 innings. 1885 would be the start of 5 consecutive seasons of 33 or more wins (36, 38 and 33 for the 1886-1888 White Stockings and 49 for the 1889 Beaneaters). His 1889 season was not as impressive as his 1885, but he did start 68 of his team's 128 games, going 49-19 and throwing 68 more complete games. After winning 26 games in 1890 and 33 more in 1891, Clarkson would have his last very good season in 1892 when he won a total of 25 games for the Beaneaters and Spiders.
Clarkson was also one of the more effective hitting pitchers the game has ever seen. His 24 career home runs ranks 7th all time among pitchers. Understandably, by age 32, his arm was shot and he had to stop pitching. That is what over 4500 innings in 12 seasons will do. After his playing career, Clarkson successfully managed a cigar store, before having a nervous breakdown from which he would never recover. In 1906, he was declared insane and spent the rest of his life in a mental institution. He would pass away at the age of 47 in 1909. Baseball enshrined him in their Hall of Fame in 1963.