Brown and Thompson each started both ends of a doubleheader on July 20th, which represented the first two games in major-league history in which more than one African-American player appeared. I actually deduced these two games for Retrosheet, based on newspaper accounts. As such, I had the opportunity to read the game accounts for these two games. Reading coverage of "Negro" baseball players, as written in 1947, can sometimes be pretty disconcerting to a reader with 2015 sensibilities. In this case, this was most especially true of the St. Louis Post-Dispatch article written by Dent McSkimming. Some excerpts of McSkimming's game story for the Browns July 20th doubleheader sweep of the Boston Red Sox are quoted here to give a flavor of how (some of) the white baseball world felt about Negro players in 1947.

"Muddy Ruel's Browns, not knowing whether to break out in cheers over their recent success or to continue to pout and growl over the presence in their team of two Negro players, are on their way east today to open a tour that will last through Aug. 4.

Before Friday's game here, the gloom that pervaded the dressing room and bench of the Browns was thick enough to make one gasp for air. Willard Brown and Henry Thompson, two Negro players, had been thrust on the team by the club owner, Dick Muckerman, the day before and the reinforcement had failed to bring the anticipated victory. So, on Friday evening, it was very apparent the majority of players were determined they would just go through the motions. Morale was low. Manager Ruel spoke in hushed tones; he was worried; anything might happen.

... At game time Saturday [the day before this doubleheader] tempers were still taut. The two Negro boys were there, in uniform, but few teammates spoke to them and they had to pair off together to get their own pre-game warmup. To add to the confused picture, [regular center fielder] Paul Lehner failed to appear at the park in time to dress for the game. Again it seemed that trouble was brewing.

What happened? The demoralized team, with Willard Brown playing in place of Lehner, gave Boston another terrific battle and lost only because Southpaw Earl Johnson shut Ellis Kinder out without a run, 1-0.

That struggle against Johnson seemed to awaken some little spark of team spirit, but it was a dull glow, indeed.

... Perhaps the two Negro boys are not responsible for the sudden improvement. As a matter of fact, they have played well but not brilliantly. But something has happened to make Muddy Ruel's team look more potent than it appeared a week ago."

The Post Dispatch story also adds a few interesting "Brownie Notes":

"Mere coincidence, but when the Browns departed from the ball park for Union Station they used a fleet of Black and White taxi-cabs.

'Thompson and Brown will be treated on this trip the same as any other player on our squad,' said Charles DeWitt, traveling secretary of the St. Louis club. He had been asked if any special arrangement was being made as to train and hotel accommodations for the two Negro players.

Leaving St. Louis, Thompson and Brown were assigned upper berths in the same car with other members of the team.

DeWitt said he knows that Jackie Robinson, Negro player with the Brooklyn Dodgers, stops with his team in most cities. Philadelphia and St. Louis are exceptions to the rule, he said. At Chicago, where there are a number of good hotels catering exclusively to Negroes, Brown and Thompson will not stay at the somewhat sedate Del Prado."

To be fair, it seems that not everybody's reaction to African-American baseball players was as negative as that of the Browns players. For example, the Chicago Tribune coverage of Larry Doby's major-league debut (which took place in Chicago against the White Sox) shows a picture of Doby posing with Indians' manager Lou Boudreau, who seems to be smiling (Doby, on the other hand, looks extremely nervous in the picture, as one might have expected given the circumstances). The New York Times noted that Doby "was introduced to the Indian players, who greeted him cordially." The Times goes on to note that "[w]hen [Doby] trotted onto the field the crowd gave him a loud round of applause" and that he "warm[ed] up with Boudreau and Coach George Susce" [Doby initially warmed up as an infielder, having played mostly second base with the Newark Eagles]. When he made his major-league debut as a pinch hitter in the seventh inning, the Times reports that he "got a rousing hand from a Comiskey park crowd of more than 18,000" and he "again was loudly applauded on the way back to the bench" (although, since this game was in Chicago, that could have been White Sox fans cheering the fact that an Indian hitter had just struck out with two runners on base).

The first African-American pitchers in the American and National leagues also debuted with the Dodgers and Indians.