lOO 
L. R. JONES 
III. The Life-History Problems 
The fact of parasitism accepted, the problem of the life history of 
the parasite at once presented itself to these early students. Kiihn's 
work on grain infection by smut (1858) and De Bary's upon the life 
histories of the Peronosporales (1863) with proof of heteroecism of the 
rusts (1864-5) set the pace. In the retiring address of my prede- 
cessor,^ we learned how Farlow brought the coals to this country which 
have kindled the fires of our best American research in mycological 
pathology. 
It should remain the first concern of plant pathologists that this 
work be continued. Discoveries as to life histories of parasites are, 
in the long run, of more practical importance as fundamental for disease 
control than demonstrations with spray mixtures. The latter are 
usually transient contributions, the former permanent. It is, there- 
fore, of good promise that the two life-history problems which first 
engaged De Bary's efforts, those of the grain rust and the potato 
fungus, are today held more open and are receiving more earnest 
attention than when De Bary died. It is well that the problem of the 
overwintering of the apple scab is no sooner settled by one investi- 
gator for one locality than it is opened by another, working in a 
different environment. Life history problems have so many vari- 
ations and complexities that they must ever remain with us, and 
progress in their fuller solution will continue as one index to general 
progress in plant pathology. 
It is fortunate that they are so well suited for thesis problems of 
graduate students, and we may hope that the traditions established 
in the laboratories of Farlow and Atkinson may be perpetuated as 
well in other institutions, 
IV. The Culture Problems 
While De Bary in Germany was laying the foundation of myco- 
logical morphology, Pasteur in France was doing a correspondingly im- 
portant work on the side of physiology, dealing with the fundamentals 
of fermentation and nutrition. Following his initial efforts, the 
problem of the pure culture with yeasts and bacteria was promptly 
defined and solved. Bacteriology not only came quickly into exist- 
ence, but soon became the most exact science of the biological group, 
^ Farlow, W. G. Loc. cit. 
