[2] In 1838, he commenced the study of the law in the offices of Jeremiah Mason and Charles B. Goodrich, the former the contemporary of Parsons, Story and Webster.

[2] During the time of pursuing his legal studies, Treat also taught as a professor in the Weld school at Jamaica Plain, near Boston, Massachusetts.

[2] While at the Weld school he was elected to take charge of the Temple Hill Academy in the Genesee Valley, New York, and there he continued his legal studies under Governor John Young.

[2] In November 1840, he resigned his position as principal of the academy in order to devote more time to his legal studies.

[1] He entered private practice in St. Louis, Missouri from 1841 to 1849,[1] after being examined and admitted to the bar by Judge Mullanphy.