“Discovering a new species is mere child’s play”

The Minakata Kumagusu Museum's “Living Slime Molds” exhibit is probably the only place where you can observe slime molds year round. Even the specimens that look like completely dried mushrooms will wriggle and squirm when put in the right environment, just like slime mold does in a petri dish.

What kind of organism is slime mold? First of all, its habitat is a humid forest. When its environment is good, it takes on an amoeba-like form, which is called “plasmodium”. When in this form, the slime mold preys on bacteria. When the conditions of its environment are not good, it spreads roots like a plant and begins to reproduce by releasing spores. The mushroom-like form that results is called a sporocarp.

They’re called “slime molds” but actually they’re very different from any kind of mold, and though they may look like mushrooms, they’re not fungi either. Plants, fungi, and animals generally have different ways of acquiring organic matter. Plants develop it themselves through the use of sunlight. Fungi acquire what they need to live by breaking down other organic substances and absorbing them. Animals eat other organisms. Slime molds are sort of like the amoebic form of an animal, but they don’t fit into any of these categories.

Western botanists focused on how to classify slime molds, but Kumagusu wasn’t interested in that. He didn’t even care if the slime molds he discovered were a new species or not.

Kumagusu looked for “life” and “death” within the slime molds. If the unmoving mushroom state was thought of as dead, then an amoebic state must be alive. But, according to Kumagusu, to botanists at the time, the amoeba form’s ejection of phlegm could also have been considered a state of death, which makes it nothing short of worthless. Instead, they would rejoice in the growth of a mushroom, believing it was living. So which state was “life” and which state was “death”? Depending on who was observing, the answer differed.

Kumagusu believed this to be the same as the cycle of death and rebirth, as told in the Nirvana Sutra of Buddhism. This world and hell are two sides of the same coin. When a sinful person is about to die in this world, a new life is on the precipice of being born and rejoiced in hell. But when the person regains their health, the new life in hell is born still, and the inhabitants of hell lament. When the person finally dies, their companions of this world will mourn and grieve, but those in hell will celebrate the arrival of new life.

The two sides of life and death are always changing. What is life, and what is death? Kumagusu was searching for the answers to these kinds of questions within the slime mold.