He is a member of the National Research council, the American association for the Advancement of Science, the American Chemical society, the American Society of Bacteriologists, the American Society of Agronomy, the American Academy of Science, the Washington Academy of Sciences and a number of other American scientific societies. He is president of the International Society of Soil Science and corresponding member of the Swedish Royal Society of Agriculture and Veterinary Medicine.
Organic Evolution from the Point of View of the Soil Investigation.
The student of soils is obliged to consider the materials from which they are made. These materials are represented by rocks and minerals, and by the remains of plants, animals, insects, bacteria and other micro-organisms. The change of rocks into soils is a slow and gradual process. In the older geological ages the mantel of soil covering the rocks was not as thick as it is today. Going back for enough, we come to the time when the depth of soil was not great enough to support plants of any but very primitive forms. Like plants and animals, our soils had to pass through a long period of change to support the varied forms of life on the earth. A direct relation may he traced between soil, plants and animals in the evolution of organic life.
Among the early forms of life there were bacteria capable of developing in a purely mineral medium. Such forms are still found in the sea, in mineral springs and in soils. Some of them can obtain the energy for their life processes by oxidizing hydrogen gas, mothane (marsh gas), carbon monoxide, sulphur, sulphuretted hydrogen, iron and even carbon. In the primitive seas, and on the rock surfaces, these simple forms of life prepared the way for the more highly organized beings. Some bacteria are able to manufacture nitrogen compounds out of the simple nitrogen gas of the air. They thus supply material out of which the protoplasm of plant and animals cells is made. Other bacteria convert the nitrogen of the plant and animal substances into ammonia and nitrates. Mineral acids, like nitrous, nitric, sulphuric and phosphoric, are partly, if not entirely, the products of bacterial activity. Carbon dioxide is generated in enormous quantities through the activities of nitro-organisms. In the course of ages the by-products of microbial activity served to dissolve cnormous quantities of rock material, and this dissolved material started on its way to the sea. Silicates, phosphates, nitrates, sulphates and carbonates, went to supply the building stones for the bodies of marine organisms. Some of the salts dissolved from the rocks ultimately became the source of salt deposits, such as rock salt, gypsum, potash, salts, limestone, etc. Bacteria are thus recognized as the primary or secondary cause of extensive mineral deposits, in other words, as geological agents of importance. By way of example, mention may be made of the potash deposits of certain European countries, estimated to be 20,000,000 years old. The green sand formation of New Jersey and states further south originated in the sea about 10,000,000 years ago. The phosphate deposits of Central Tennessee are derived from limestone rock 50,000,000 years old at the very lowest estimate. The extensive deposits of coal represent the remains of the ancient vegetation. We are now burning coal derived from plants that grew at least 20,000,000 years ago. The coal deposits contain nitrogen which today is the source of fertilizer. In making coke, illuminating gas and other products from coal, a large part of the nitrogen is saved and converted into ammonia for refrigeration and fertilizer purposes. We know of extensive deposits of sulphur which originated millions of years ago and which today are used for industrial and agricultural purposes. In a smaller way, mention may be made of deposits of iron ore, gypsum, or limestone, in the formation of which basteria played an important part.
