Sludged Blood

One of medicine's big mysteries is the bodily process that translates disease into death. One man who has been stubbornly looking for an answer is 43-year-old Dr. Melvin H. Knisely, a gaunt, tall (6 ft. 3) physiologist at the University of Chicago. For 17 years, Dr. Knisely and a squad of co-workers at Chicago and the University of Tennessee have been bending over their microscopes, laboriously studying the circulation of the blood. Last fortnight, Science published their epochal findings.

Using a special quartz-rod light that he developed himself to make blood vessels transparent and three-dimensional under the microscope (TIME, Nov. 18, 1940),

Knisely began by examining blood circulation in healthy animals. In all normal animals (including human beings) the red blood cells float separately in plasma like tiny fish in a rapid stream. They flow along freely and often so swiftly that the individual cells cannot be distinguished under a microscope. A normal red cell keeps to itself.

One day Knisely was peering into the blood vessels of a monkey with malaria. He found a radical change in the red cells: instead of flowing independently, they were clumped together in sluggish masses. Knisely and his group went on to study the circulation in other diseased animals. Sure enough, sludged blood turned up in every animal and human being suffering from severe injury or disease. All told, they found red-cell clumping associated with over 50 conditions, from the common cold to hysteria.

What makes the red cells stick together? A member of Knisely's group has already discovered an important clue: a sticky coating on the cells (not found in normal blood) has tentatively been identified as a protein. Somehow disease or injury causes the body to deposit this sticky material on the red cells.

The results may be "utterly devastating." The body's smallest blood vessels are barely wide enough to let a single red cell squeeze through. When red cells clump, they plug these bottlenecks and deprive tissues of food and oxygen. The tissue cells die. When sludged blood kills important tissues, the patient dies.

Others have seen sludged blood before, but its significance had not been understood. Dr. Knisely thinks that red-cell clumping may account for many cases of mental illness (he found the central nervous system of one psychotic patient "showered with permanent plugs" that had destroyed many of the nerve cells). And he suggests that even aging and senility may be accounted for by accumulated damage from injuries and illnesses.

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