SELECT COUNT("Enrollment") FROM table_37201 WHERE "Affiliation" = 'public' AND "Founded" < '1866'
What is the total enrollment for an affiliation of public, and was founded before 1866?
CREATE TABLE table_37201 (
    "School" text,
    "Location" text,
    "Founded" real,
    "Affiliation" text,
    "Enrollment" real,
    "Nickname" text,
    "Primary conference" text
)