The Doppler Effect and the Redshifts of the Galaxies

The Doppler Effect had only been discovered less than a century before. People could imagine other possible explanations for why the redshifts might occur. Edwin Hubble always hedged his bets, and didn't want to say that the apparent velocities were real. Marcia Bartouciak explains the perplexity at the time. What did it all mean? Were these swift velocities even genuine?