Here’s a photo from the November 19 1948 edition of the Toronto Globe and Mail, showing Toronto’s oldest practicing lawyer at that time.

Mr. Brown would have been born in 1855, making him 12 years older than the country he was living in.
Since I was ghoulishly curious, I traced him in the Toronto city directories. He appeared in the 1953 city directory, so he made it into his 98th year, but he doesn’t appear in the 1954 directory.
I also looked back in old city directories. There is a Merritt A. Brown working as a barrister, notary public and patent attorney in the 1900 city directory. And he placed an ad in the 1902 directory:

He might go back even further, but that’s as far as I looked. Even then, he would have been considered middle-aged: he would have turned 45 at the turn of the 20th century.