In 1841 and 1842, the first two years of the Trail's use by emigrant parties, the overland route ended at Fort Walla Walla, at the mouth of the Walla Walla River. From there, emigrants rafted their wagons down the Columbia River to the Willamette River Valley.
I have been an insulin dependent diabetic for 20 years. I had my first ever cortison injection for a worn out knee. For 5 days after the injection my blood sugar levels ran between 450 and 600. No matter how much fast acting insulin I took, it would not go down.
At these times, stimulation testing with Synacthen, glucagon or insulin are used and it is necessary to understand the interference by the synthetic glucocorticoid. Dexamethasone does not cross react with the cortisol assays and is not a problem. Dexamethasone has a half-life of 4-5 hours. Prednisolone does cross react with the assays (30% with most commercially available assays). Prednisolone has a half-life of ~3.5 hours and so needs 16-18 hours to be adequately cleared from the circulation.