After his parents moved to New Jersey, Mendels was employed at a brokerage house during the post war boom period.
"[1] After four years of working in the brokerage firm, he left his position to be a full-time curbstone broker in Manhattan.
[5] In 1904, Mendels began to actively attempt to organize the curb to reduce swindling and valueless stocks.
[5] Around 1895, Mendels began promoting the idea of the moving the market indoors which wouldn't be actively picked up for two more decades.
Around late 1907, Mendels began devoting most of his time to keeping the Curb market "free of swindling stocks.
On February 26, 1909, he gave a "very complete and satisfactory" testimony to the Wall Street Investigating Committee on how the curb brokers conducted business under his authority.
[7] On November 10, 1909, Mendels issued a notice reading, "For the protection of the public, complaints made in writing against any corporation or individual using the New York Curb market, directly or indirectly, will be investigated by the agency and referred to the proper authorities for suitable action.