NoTKS AND COMMKNT. 179 



rubber — fit e:i\blem of all that is tough, elastic and formless in 

 modern Hfe and morals! None the less it is a matter of congratu- 

 lation that a nmnber of Avell known botanists have engaged in a 

 thorough investigation of certain rubber-producing plants, 

 and there is every reason to expect that the better knowledge 

 thus obtained of actual conditions of growth and reproduction 

 will eliminate something at least of the speculative element 

 in the future history of this indispensable product. One of the 

 latest to devote himself to this investigation is Dr. J. B. Mc- 

 Callum, of the Arizona Experim.ent Station, who will carry on 

 his practical w^ork in large part at the Desert Laboratory at 

 Tucson. 



The program of the Fourth Session of the Graduate School 

 of Agriculture, which will be held July 4-29, at Ames, Iowa, 

 includes lectures on Plant Physiology and Pathology as follows: 



Dr. C. E. Bessey: A Little Embryology. The "Water 

 Departm.ent" of Plants. The Great Business of Plants. Plant 

 Eggs and Sperms. The Sun and the Plant. 



Dr. D. T. MacDougal: Physiology of Genetics. Acclima- 

 tization. Direct Influence of External Factors on Plants. 

 Ovarial Treatment of Plants. Desert Vegetation. 



Prof. Haven Metcalf: Forest Pathology. Diseases of 

 Ornamental Trees and Tree Surgery. New or Little-Known 

 Laboratory Methods and Apparatus. Plant Diseases and 

 Legislation. Bibliographical Methods in Plant Pathology. 



Dr. L. H. Pammel: The History of Vegetable Pathology. 

 The Factors Controlling the Diseases of Plants. The Ustilag- 

 ineae Affecting Cereal Plants. The Uredineae Affecting Cereal 

 and Other Plants. Certain Root-Rot Diseases of Plants. 



Dr. G. E. Stone: General Principles of Plant Physiology, 



Dr. F. L. Stevens: History and Development of Plant 

 Pathology. The Consideration of the Needs of Present Plant 

 Pathology. Discussion of the Pedagogy of Plant Pathology. 

 Soil Diseases. 



Dr. E. Von Tschermak: Conditions of Blossoming, with 

 Special Reference to Pollination and Infection from Rust and 

 Smut. Questions of Fecundation and Transmission, (Two 

 lectures.) The Problem of Correlation with Special Reference 



