Still's Disease Foundation has become stillsdisease.org and is maintained by Jennifer Jay. If you want to continue your study, that is the place to go. In 1897 George Still drew attention of doctors who were working with rheumatoid arthritis when he collected a number of children who had similar symptoms which didn't fit into any category at that time. It's now being questioned whether there is really only one form, as most of us who have met on the internet suspect. Earlier than those dates, sufferers were diagnosed as having other conditions and names.
Diagnosis is still a challenge, and is usually given by a process of elimination.
Yet, those of us who have met on the internet agree that, although each of us is different, yet, we are somehow alike, or related. Descriptions of symptoms vary, but usually includes a fever that rises and falls, usually rhythmically, weakness, sweating, muscle and joint pain which often moves throughout various parts of the body, rheumatoid arthritis, there is often a rash which itches in some people, and other vague feelings. In some people the fever can be very high, as high as 106 f. Weakness and pain can be so severe as to completely disable the patient. There are also clinical features which I will leave for doctors to understand which can include the heart, lungs, liver, blood, bones, spleen, and more. Descriptions of the seriousness of the disease varies, but it is generally decided that there are usually periods of remission and activity, in varying amounts.