CATALOG 1952-1953 473

 PS. 528.-Statistical Mechanics and Thermodynamics. 3 hours. 3 credits.
Prerequisite: PS. 501 and 512. Not offered 1952-53.
 Classical treatment of the first and second laws of thermodynamics. Thermody-
namic concepts and relations; application to systems of one or more components and
phases. The Nernst heat theorem and the so-called third law. The methods of statistical
mechanics; partition functions; canonical ensembles. Derivation of the laws of thermo-
dynamics. Modern concept of entropy; quantum-mechanical treatment of the third law.
 PS. 529.-Relativity. 3 hours. 3 credits. Prerequisite: MS. 507. Not of-
fered 1952-53.
 An introduction to Einstein's theory of special and general relativity employing
tensor analysis. The treatment, in general, will follow that in the text by P. G. Berg-
mann.
 PS. 530. (Formerly PS. 513).-Special Topics. Variable credit. Offered
1, 2, 3.
 Experiments on a particular topic of physics, a review of classical experiments, or
the development of an assigned experimental problem. The work will be assigned to
meet the needs and interests of the particular student.
 PS. 550.-Colloquium. 1 hour. No credit. Offered 1, 2.
 Students and staff members will report on their own research, topics of general
interest, or on papers in the current literature.
 PS. 568.-Biophysics. 3 hours. 3 credits. Prerequisite: PS. 320, one year
of chemistry and one year of biology. Offered 1.
 Radioactivity. Passage of radiation through matter. Actions of radiation on living
cells, including bacteria, rickettsia and viruses. The electron microscope; instruments for
detection and measurement of radiation. Study of bio-electric phenomena; electro-
phoresis; properties of colloids. Theory of Brownian movement applied to the phe-
nomena of osmosis and diffusion. Surface phenomena; chromatography.

 PLANT PATHOLOGY

 Instructional Staff 1951-1952
 Tisdale, W. B., Chairman, Division of Botany; Weber, G. F., Owen, J. H.
 Prerequisites to any course in Plant Pathology are Botany 101 and 102.
 PT. 321.-Plant Pathology. 1 hour, and 4 hours laboratory. 3 credits.
Prerequisite to courses in Plant Pathology except PT. 325 and PT. 434. Of-
fered 1, 3.
 Plant diseases caused by mechanical injury, environmental factors, parasitic bac-
teria, fungi and other plants and their economic importance; life cycles and role of
parasitic fungi and bacteria; methods of control of plant disease.
 PT. 325.-Forest Pathology. 1 hour, and 4 hours laboratory. 3 credits.
Offered 2, 3.
 For forestry students. Tree diseases caused by mechanical injury, environmental
factors, parasitic bacteria, fungi and other plants; life cycles and role of parasitic fungi
and bacteria; the economic importance and control of plant disease.
 PT. 421.-Fungicides. 1 hour, and 4 hours laboratory. 3 credits. Of-
fered 1.
 Fundamental composition, methods of preparation, manner of application and limits
of safety as manifested by detrimental effects of fungicidal sprays and dusts.
The statement "Offered 1" means offered first semester; 2, second semester; 3, summer session.