Vol. 43 TORREYA December 1943 



Phytopathology— 1867-1942* 



George M. Reed 



The three decades 1850-1880 are noted for fundamental discoveries in the 

 field of biology. In 1859 Charles Darwin published "The Origin of Species," 

 a work which changed completely the viewpoint in biology. In 1865 Gregor 

 Mendel published the results of his experiments on inheritance in peas, an ac- 

 count which made no impression upon his own generation, but proved to be 

 the keystone of genetic investigation in the early twentieth century. Louis Pas- 

 teur, in 1855-1859, carried out his researches on fermentation, maintaining 

 that the changes which occurred in various organic substances were the result 

 of the activity of micro-organisms, instead of purely chemical processes in 

 which the observed rods were supposed to originate as by-products. In 1860- 

 1864 he was engaged in experiments on the problem of spontaneous genera- 

 tion. It was almost universally believed that the micro-organisms originated 

 from the decomposition of higher plants and animals. The fungi associated 

 with plant diseases were thought to arise from changes in the higher plants of 

 unknown causal origin. In 1865-1870 he carried out his classic studies on the 

 silkworm disease, demonstrating the microbic origin, not of one disease only, 

 but of two. Robert Koch, in 1876, supplied decisive evidence that anthrax of 

 cattle was due to a microscopic rod-shaped organism which had been associated 

 with this malady by Devaine and Rayer in 1850. Koch's results were confirmed 

 by Pasteur in 1881, who carried out his experiments on the prevention of an- 

 thrax of sheep by vaccination. 



L. R. and C. Tulasne, in 1861, published the first volume of their standard 

 work on the fungi, describing in great detail the life history and structure of 

 the powdery mildews. In 1863 Anton de Bary worked out the life history of a 

 powdery mildew, Sphaerotheca castagnei, on dandelion, describing the appear- 

 ance of the sex organs. De Bary's most important work, however, was pub- 

 lished in 1865, when he recorded heteroecism in Puccinia grmninis. Previous to 

 the work of Tulasne, de Bary, and others, the nature of the lower fungi was 

 quite misunderstood and the idea that they were the cause of various diseases 

 was not accepted. The demonstration of the polymorphism of the rusts, in- 

 volving four or five spore stages, was a great advance in our knowledge. It 

 was, of course, difficult for that generation to accept the view that a rust was 

 not only parasitic, but required at least two different hosts in order to complete 

 its life cycle of four or five types of spores. 



* Presented at the 7Sth Anniversary Celebration of the Torrey Botanical Club at the 

 Brooklyn Botanic Garden, Thursday, June 25, 1942. 



Brooklyn Botanic Garden Contributions No. 99. 



155 



