66 



Rostpilze," Versuch einer Gesamtdarstellung ihrer biologischen Verhaltnisse. 

 Berlin 1904. Gebr. Borntrager. A chronological table gives a list of the 

 heteroecious rust fungi discovered since de Bary's first investigations made 

 in 1864 with Puccinia graiiiinis. The text treats in the greatest detail and 

 with pertinent bibliographical references, gradation of differences, hmi- 

 tation of species, specialization and theory of descent, susceptibility and 

 transmission of rust diseases in seed. With this is also discussed thoroughly 

 the mycoplasm theory brought forward about 1897 by Eriksson. This point 

 has already been discussed (see p. 34). Eriksson's latest studies appeared in 

 1904 in the publications of the Schwed. Akad. d. Wissensch. under the title : 

 "Das Vegetative Leben der Getreiderostpilze." 



A further important advance in the creation of scientific foundations is 

 eliown in the "Pathologischc Pflanzenanatomie" by Ernst Kiister, Jena 1903, 

 published by Gustav Fischer. Guided by the discovery that a distinct sepa- 

 ration of the natural forms into normal or abnormal can not be carried out, 

 Kiister tests the phenomena from the physiological point of view, i. e. as to 

 the functional efficiency of the tissues. "The tissues are prevented from de- 

 veloping into functionally efficient, i. e. normal tissues, by influences of some 

 kind or functionally efficient tissues undergo subsequent changes in which 

 they forfeit entirely or partially their functional ability, or new tissues are 

 produced in the plant body of such a nature that its diseased and deformed 

 organs either accomplish nothing for the organism as a whole, or less than 

 those which we designate as normal." We find in this work a successful 

 attempt at presenting the developmental mechanics of the vegetable organism. 



A periodical literature developed along with the attempts to organize 

 the protection of plants. The guiding principle was the practical question, 

 how the spread of disease and the enemies of cultivated plants may best be 

 prevented and how their direct control can be most advantageously accom- 

 plished. 



This question w^as considered more closely first in the United States of 

 North America, since in 1887 stations were formed by the Department of 

 Agriculture for the study of phytopathology and of insects. These most 

 active institutes and experiment stations first of all issued annual reports and 

 then later special publications of scientific investigations. The report of 

 1889^ gives a closer insight into the organization of the service. W^e 

 learn from it that the Phytopathological Division published its investigations 

 in a definite periodical "The Journal of Mycology" and also distributed pop- 

 ular bulletins of some of the most important diseases. Correspondence con- 

 sisting of replies to queries consumes much of the activity of these stations. 

 For example, in 1889 the questions sent by practical agriculturalists de- 

 manded 2500 replies. These scientists desire chiefly to test results of lab- 



1 Report of the chief of the Division of Vegetable Pathology for the year 1889. 

 Published by the authority of the Secretary of Agriculture. Washington 1890. 



