The phrase "a course by which" is correct and usable in written English.
It can be used to describe a method or pathway to achieve a particular goal or outcome.
Example: "The university offers a course by which students can earn a degree in environmental science."
Alternatives: "a method through which" or "a way in which".
Brennan believed he had set a reasonable course by which the Court could draw a line between obscenity and speech that the Constitution intended to be free, yet what Justice John Harlan later described as "the intractable obscenity problem" only got worse.
Compared with expression of CCL2, the time course by which TNFα elicited an increase in ICAM-1 expression was slightly delayed, reflecting differential temporal dynamics consistent with their respective physiological roles in leucocyte recruitment and extravasation (Springer, 1994; Raab et al., 2002).
Vico asserted that the influential Cartesian treatise The Port-Royal Logic, by the Jansenists Antoine Arnauld and Pierre Nicole, inverted the natural course by which children learn by insisting on a training in logic at the beginning of the educational process.
She did clean it eventually, of course, by which times its doggy contribution had dried to a fine powder.
Yet another follows the course by which the Bank of Commerce and Credit, International (B.C.C.I).
Pop, of course, by which I mean lemonade, limeade, cherryade and, best of all, Tizer.
After the war he set the course by which the Soviet armed forces eventually reached their high levels during the Cold War.
Akbar Hashemi Rafsanjani, a former president who lost to Mr Ahmadinejad in last year's election, recently predicted that the diversion of the nuclear programme from its "natural course", by which he meant the reference of Iran to the Security Council, would cause "lots of problems for us".
It is tempting to propose that the slow time course of retinal degeneration reflects the slow rate of A2E accumulation, coupled with the slow time course by which it induces cell death.
Although it has been well recognized that exposure to secondhand tobacco smoke (SHS) is associated with cardiovascular mortality, the mechanisms and time course by which SHS exposure may lead to cardiovascular effects are still being explored.
