Of all the natural phenomena that I have seen during my voyages few have produced a greater impression than the palo de vaca. What moved me so deeply was not the proud shadows of the jungles, nor the majestic flow of the rivers, nor the mountains covered with eternal snows, but a few drops of a vegetable juice that brings to mind all the power and fertility of nature. On a barren rocky wall grows a tree with dry leathery leaves; its large woody roots hardly dig into the rocky ground. For months not a drop of rain wets its leaves; the branches appear dry, dead. But if you perforate the trunk, especially at dawn, a sweet nutritious milk pours out. (82)