V. Listen to the recording of the text and reproduce it:

Michurin is well-khown in the history of breeders. As a boy, he became interested in plants and his ability to recognize valuable traits soon became evident. He applied his marvelous powers of observation in developing new types of plants. He could detect traits that were not easily seen by others, and his great patience made it possible for him to carry on experiments that lasted for fnany years. He often combined the traits of two different plants to make a new yariety. He spent many hours carefully transferring pollert from one plant to the pistils of another. In this way he crossed a plum and an apricot to produce a new fruit.

VI. Translate the text in writing with a dictionary paying attention to infinitive constructions (you are given 30 min.)

a) The units of living matter cover a wide range of sizes. A few sorts of cells are large enough to be seen by the unaided eye; to be seen, they must be at least 0.1 millimeters, or 100 microns, in one dimension. Many animal eggs, which are single cells, are this large. Among the few plant cells which are this large are the cells in the fleshy portion of the watermelon. Most cells are smaller than this and are said to be microscppic in size; that is, within, the range of an ordinary light microscope. Below this range is another into which fall the viruses. Particles of known viruses generally occupy the size range 100 to 1 000 A or 10 to 100 millimicrons. Thus, viruses are individually invisible in the light microscope and are said to be submicroscopic, although they can be visualized with the electron microscope. Within this same size range fall several aggregations of molecules which make up the structural components of many types of cells. Between the viruses which have not been demonstrated to have cellular organization, and the bacteria, which have been demonstra- demonstrated to have a characteristic type of cellular organization, falls a group of organisms known as the Rickettsias. The Rickettsias ^re considered by some investigators to be cellular; by others to be noncellular and perhaps similar to the viruses.

b) The chemical analysis of plants is to show what the plant contains, what food it requires; the chemical analysis of the soil is to show what the tatter lacks; a comparison of the results of the first analysis with those of the second will give an answer as to how soil fertility \s to be raised. The result of this analysis cannot be considered complete unless it is concluded by a summarized synthesis. Besides, both the physical and the chemical analysis of. the soil are needed. But neither the one nor the other taken separately, nor both together, can solve the problem of

soil fertility, still less the problem of the development of fertility, of the development of soils. This evolution can be understood only if we study soil as a developing integral whole governed by the activity of plant and animal organisms. We cannot imagine either the origin or the ior-% mation of soil without the direct participation of plants? Plant physiology is the principal basis of all the conclusions of agricultural science. If the soils of today are to be cleared of plants for a number of years it will rapidly lose its fertility and become barreh dust.

VII. Read and tell about any great biologist. (see OUTSTANDING BIOLOGISITS)