476 THE POPULAR SCIENCE MONTHLY 



The most important advance in prophylactic procedure came with 

 the introduction of the Bordeaux mixture, a compound of lime, blue- 

 stone and water, by Millardet in 3885. Since that date the battle 

 has waged fiercely with successive conquests for plant pathology. Now 

 many of the most important diseases are well understood and many 

 successful modes of treatment have been devised. 



Some of these with their most significant dates are represented in 

 Table I. 



During the seventies there were only two or three investigators in 

 plant pathology in America. This number rapidly increased until 

 between 1888 and 1900 over 4,000 papers upon this subject appeared. 

 Only a few dozen economic plant diseases had been even cursorily 

 described prior to 1880, while to-day a total of over 500, more than 

 250 of them serious, have been investigated. Countless diseases of wild 

 plants also are now known more or less completely. 



To enable comparison of the real advance made in plant pathology 

 with the advances made in the sister fields of veterinary medicine and 

 human medicine, two tables are given summarizing the history of 

 these two fields as regards a few of the most important diseases (tables 

 11. and III.). 



That plant pathology has made such a relatively good showing not- 

 withstanding her tardy start is due to the late influence of the germ 

 theory of disease in all of these fields. 



With the continual increase of plant diseases in both number and 

 aggressiveness every effort of the plant pathologist will be required to 

 increase the efficiency of treatment. So also is there great need of a 

 public opinion favoring rational plant sanitation. The chief diseases 

 now prevalent as well as those which are liable to invade any section in 

 the near future should be known to all plant producers. Especially 

 needed are laws properly enforced to restrict the migration of diseases. 



