"The danger to people suffering from heart trouble coming into high altitudes is grossly exaggerated," says Dr. Edward C. Schneider, one of the Anglo-American expedition. "The rate of circulation is not materially increased. The blood-pressure on the Peak is not increased; it is even lowered. The heart--if a person exercises--may beat a little faster but it does not pump any more blood. The pulse is a little more rapid. If a man suffering from heart trouble rode up the peak on a train, remained in his seat, and did not exert himself physically, his heart would not beat a bit faster at the summit than when he left Manitou. But if he walked about on the summit there would be a change, for the exercise would make the heart work harder." But exercise is not injurious; it is beneficial. As I found in guiding on Long's Peak, the rarefied air of the heights was often stimulating, especially to the tongue. Rarefied air is likened by the scientists to "laughing-gas" and furnishes a plausible explanation of the queerness which characterizes the action of many people on mountain-summits. "We saw many visitors at the summit," said Dr. Schneider in explaining this phase, "who appeared to be intoxicated. But there was no smell of liquor on their breath. They were intoxicated with rarefied atmosphere, not with alcohol. The peculiar effects of laughing-gas and carbon-monoxide gas on people are due to the lack of oxygen in the gas; and the same applies to the air at high altitudes." The summit of Pike's Peak is roomy and comparatively level, and is composed of broken granite, many of the pieces being of large size. A stone house stands upon the top. In this for many years was a government weather-observer. A weather station has just been re-established on its summit. This will be one of a line of high weather stations extending across the continent. This unique station should contribute continuously to the weather news and steadily add to the sum of climatic knowledge. This one peak has on its high and broken slopes a majority of the earth's climatic zones, and a numerous array of the earth's countless kinds of plant and animal life. One may in two hours go from base to summit and pass through as many life zones as though he had traveled northward into the Arctic Circle. Going from base to summit, one would start in the Upper Sonoran Zone, pass through the Transition, Canadian, and Hudsonian Zones, and enter the Arctic-Alpine Zone. The peak has a number of places which exhibit the complexity of climatic zones. In a deep cañon near Minnehaha Falls, two zones may be seen side by side on opposite sides of a deep, narrow cañon. The north side of the cañon, exposed to the sun, has such plants as are found in the Transition Zone, while the cool south side has an Hudsonian flora. Here is almost an actual contact of two zones that outside the mountains are separated by approximately two thousand miles.