THE UNGERIAN PERIOD 39 



Pflanzen-Teratologie. The manuscript for the first 

 volume was largely completed before his death and was 

 published a year later by his friend, Nees von Esenbeck 

 (see Vorerinnerung in same, V-VIII). 



Meyen's Pflanzen Pathologic is really only a careful 

 classification and description of a large number of dis- 

 eases. There is wanting in the book those general or 

 introductory chapters in which authors are wont to set 

 forth their generalizations and philosophies. We do not 

 have, therefore, a summarized or organized statement 

 of his ideas with respect to the nature of disease, the 

 relation of the fungi found associated with disease lesions, 

 and other fundamental pathologic theories so extensively 

 set forth by Unger and even by Wiegmann. His early 

 death is doubtless responsible for these omissions. The 

 book gives one the impression of incompleteness. From 

 his description of the smuts, the rusts, and the mildews 

 it is, however, readily seen that his philosophy of disease 

 in plants is not materially different from that of his 

 phytopatho logic contemporaries. His philosophy of 

 disease, the nature of parasitic fungi, and their relation 

 to their host plants is clearly indicated in a short paper 

 on the development of smut in the maize plant. 1 He 

 says it is an established fact that the cereal smut is not 

 an infectious disease, but is one due to a stagnation of 

 sap brought about by excessive and unnatural fertilizing. 

 He describes and figures the formation of the spores as 

 taking place within the host cells, and calls them pseudo- 

 organisms, the product of abnormal nutrition. His 



1 Meyen, F. J. F. : Beitrage zur Pflanzenphysiologie. I. Uber die 

 Entwickelung des Getreidebrandes in der Mays Pflanze, Archiv. f. 

 Naturgesch., 1 : 417-421, 1837. 



