The guy from the Blood-Horse doesn't know what he's talking about. Donald Macdonald's last race that I can find on the DRF Archives was a 4th place finish as a 12-year-old in the 6th race at Havana Cuba on March 16th 1918. Perhaps he's looking at his final 22 wins and not his 1913 races.
In those days - they did not put the actual date in the Daily Racing Form past performances - they put index numbers in the place of the dates.
Races with index numbers 6,807 Through index numbers 12,943 occured in the year 1913.
His first win of the year 1913 was race "6991" - it was the 5th race on Jan 29th of 1913. Here is a chart of the first race on that card...
6987 is race 1, 6988 is race 2, 6989 is race 3, 6990 is race 4, 6991 is race 5 and so on.
Here's a chart of one of his wins ... this was the 3rd race at Havre De Grace on Sept 15th of 1913.
In those days - the serious handicappers would buy monthly chart books - and the charts were in numerical order.