(The Nissl method, by the way, is still in use. Nissl, a friend and close collaborator of Alzheimer, became a medical school legend with his instructions on how to time the staining process: Take the brain out, he advised. Put it on the desk. Spit on the floor. When the spit is dry, put the brain in alcohol.)

Image Credit... Katherine Streeter

With Auguste Deter’s brain tissue fixed, frozen, sliced, stained and pressed between two thin pieces of glass, Alzheimer put down his habitual cigar, removed his pince-nez, and peered into his state-of-the-art Zeiss microscope. Then, at a magnification of several hundred times, he finally saw her disease.

It looked like measles, or chicken pox, of the brain. The cortex was speckled with crusty brown clumps — we now call them plaques — too many to count. They varied in size, shape and texture and seemed to be a hodgepodge of granules and short, crooked threads, as if they were sticky magnets for microscopic trash.

The plaques were nestled between the neurons, blocking their communication with one another. They were so prominent that Alzheimer could see them without any stain at all, but they showed up best in a blend of magenta red, indigo carmine and picric acid.

A different stain revealed what Alzheimer called “a tangled bundle of fibrils” — weedy, menacing strands of rope bundled densely together. These tangles grew inside the nerve cells, strangling them.

Auguste Deter had not lost herself. Rather, her “self” was taken from her.

On Nov. 3, 1906, Alzheimer presented his findings at the 37th meeting of South-West German Psychiatrists with a paper titled, “Regarding a Curious Disease of the Cortex.” What he did not realize was that these very same plaques and tangles were not just responsible for this rare, middle-aged dementia, but also for the majority of cases of senile dementia.

Nor could he have foreseen that with the significant rise in longevity over the 20th century, cases of Alzheimer’s disease would skyrocket into the millions. Paradoxically, we have created a civilization of such health and longevity that a disease that was once rare now threatens us all.