For those folks who have a library of MS-related books, I recommend the first acquired book be Multiple Sclerosis: The History of a Disease by T. Jock Murray, OC, MD.
The second should be The Multiple Sclerosis Diet Book by Roy L. Swank, MD, PhD & Barbara Brewer Dugan. First published in 1959 and most recently again in 1987, it is often referred to in MS information. In my opinion, much of its information is outdated and even incorrect; for example, I do not support the low-fat diet idea for anyone. (I believe we need fat in our diet in order to be healthy, to manufacture myelin and hormones; we don't need carbohydrates.)
I find his ideas on the genesis of the disease plausible. Page 81
The random distribution of the symptoms and accompanying neuorological signs, and the frequent location of the pathological lesions (plaques, or areas of demyelination) in the brain and spinal cord surrounding small venous channels, suggest that the small blood vessels (microcirculation), which include the arterioles, capillaries, and venules, play a role in the genesis of this disease. This contention has been supported by the observations that small arterioles and venules of the brain and spinal cord are thickened, often tortuous, nodular, and alternately constricted and dilated, and by the occasional accumulations of platelets (thrombocytes) and small blood clots in small central venules inside the demyelinated lesions.
In other studies, it was found that blood serum from multiple sclerosis patients (also from normal subjects) caused reversible demyelination of cultured nerve fibers and also blocked the passage of nerve impulses through these fibers.
Swank and his collaborators showed that infusions of normal plasma into multiple sclerosis patients in exacerbation resulted in a rapid recovery of the patient, especially in the early phases of the disease.
If evidence has pointed to blood and the bloodstream, I am disappointed that researchers have not examined there thoroughly first! A few are starting now, I guess.