Fifty years ago, in a small clearing deep in the Peruvian Amazon, I met a man who would change my life as a doctor forever. He didn’t speak English or even Spanish. He was an Aquarauna hechiccero-curandero (witch/healer/shaman) to whom I had been brought by a young man I had met in a small town in the north.

We first saw him from the back. He was dark, stocky, broad shouldered, bare-chested and wore loose trousers of a coarse material. His hair was grey and hung straight down to the middle of his back. Even from the back, his presence was powerful and intimidating.

My guide and I waited respectfully at the entrance of his large hut without speaking. It seemed like a very long time before he abruptly turned around. My heart practically leapt out of my chest with terror when I saw his menacing necklace of small skulls, feathers, human hair and what appeared to be the teeth of large jungle cats.

I had been told there were headhunters in the region. As a Norte Americano medical student, I didn’t want my head adorning a warrior’s chest; I was relieved upon second glance to see that the skulls were those of birds. I was so startled by his necklace, however, that I was still frightened when I finally looked up at his cragged face.

Never before or since have I seen eyes like his. They were pitch black, shining like onyx. They were deeply set in his ancient face and seemed to open into infinity. I was still scared and unsure of his intentions, and searched those eyes for a sign. He gazed at me, seeming to read my thoughts, and gestured for me to follow him.

Without a word, he took me to a hut on the other side of the clearing and signaled for my guide to wait. He walked in front of me and, free from his intense stare, I started to get some of my fear under control, I noticed his gait. He walks like a cat, I said to myself. The grace and certainty with which he moved was as striking as his presence, his eyes and his silence.

No words had been exchanged, and yet he was guiding me as if he already knew very well; not only who I was, but also how I had come to this moment in which the two of us were together. We seemed to be connected in some way that I couldn’t put my finger on.

Inside the hut, he stood patiently while my eyes to adjust to the dark interior. On the far wall I could finally see a single straw cot raised four or five feet from the ground. On it lay a man with his back to us, facing the wall. He didn’t move. He breathed slowly, deeply. He was well developed and well nourished. He was well hydrated. I could see a steady pulse in the arteries of his neck.

Of course! This mysterious curandero was asking for my opinion. I was on clinical rounds! Now we were doing something I could relate to. I was brought back to my time at medical school, following my professors around to see their patients. Immediately, I fell into the familiar role of fellow doctor and felt at ease.

Still without a word having been exchanged, we walked back to the first hut and to my translator and guide. The curandero turned to my guide and said a few words in his native language. “What do you think?” he had asked.

Eagerly, I offered my prognosis. The patient was young, healthy, well developed, breathing well with a strong pulse: “He should be fine,” I said, looking at my hands as if notes were written on them.

I looked up into those infinitely black, incredibly peaceful eyes and heard a voice inside my head saying, No.

I don’t think it occurred to me that he had never actually spoken the word, No. My words stumbled over each other as I tried to explain my medical opinion, but I began to lose myself in his eyes that now seemed somehow connected or locked into mine. What was happening? What do you mean? Let me examine him further! He is going to be fine – I will show you!

Without shaking his head or saying a word, the shaman once again spoke inside my head: No, he is going to die.

In my years around doctors, hospital clinics, emergency rooms, operating rooms and all else involved in the training of a modern doctor, I have never felt such calm certainty: He is going to die.

“But why?” I blurted out in Spanish.

I heard the translator as I fell back into the sea of the shaman’s eyes: “Because the signs say so.”

This was a revelation to me. Within the span of a few seconds, a thousand thoughts ran through my head: Signs from where? Was this like Voodoo? Why had I been brought here if the shaman was resigned to that man’s fate? Wasn’t there something we could do? Would this witch doctor, whom I still was scared of and still did not entirely trust, blame me? Was I one of the signs? And did he really speak inside my head, without making a sound?

There I was, a highly skilled doctor in the middle of the jungle with a man who could read my mind and insert his own thoughts as well. He probably had followed my entire train of thought just then. I gathered myself and through the translator this time – a mode of conversing I found much less terrifying than telepathy – I learned more about the patient.

The sign that made his death a foregone conclusion was that he had turned to face the wall. It was as maddeningly simple as that. No tests, blood samples, or highly advanced machinery would have brought about the same level of certainty to this shaman or, at this point, to me as well.

What the medicine man in the jungle had taught me were two very important things. The first was that telepathy was not just a myth – I had experienced it myself, and although I had no clinical explanation for it, I knew it as well as I know my name that we had communicated without using words.

The second – and one I think of to this day as I treat my patients – is that there are signs that can’t be found in a diagnostic manual or test results that indicate the status of a patient. It’s changed the way I observe my patients, and it has honed my sensitivity to their symptoms – both the ones they describe, and the ones they don’t even know they’re showing.