General Conclusion 503 



engaged our thoughts, and it is hardly necessary to dwell 

 further on this feature of the time. But it may be recalled for 

 a moment to point out that we have been thereby furnished 

 with not only one, but many points of departure from 

 which lines of investigation are spreading out widely during 

 the new century. Cytology and oecology have attracted 

 many followers, and both anatomy and physiology have 

 received copious illustration from their work. Still greater 

 importance may be attached to the development of veget- 

 able pathology, for it possesses not only scientific interest, 

 but is likely to lead to results of very great economic 

 value. Regarded side by side with the same subject in the 

 animal kingdom, its achievements certainly seem extremely 

 small, but several directions for its development are indi- 

 cated. A few experiments were directed in the closing 

 years of the century to the fascinating problem of securing 

 immunity from disease, though most of the work on this 

 subject, small as it is, has been done since 1900. Bacteria 

 as the source of disease in plants have begun to be scruti- 

 nized, though very little accurate information has been 

 forthcoming. The development of this section remains as 

 a problem for the new century. 



The application of research in vegetable physiology to 

 the problems of agriculture we have seen was a feature of 

 the whole period under review. At its close those problems 

 were as insistent as at any time during its progress. Though, 

 as we have seen, many new facts were ascertained, they 

 gave rise themselves to further inquiry and new questions 

 continually came to the front. Among the latter, good 

 results have already been obtained by the study of the 

 problems of heredity, hybridization, variation, and kindred 

 subjects, and botanical questions are competing in interest 

 with those of zoology. 



Besides these developments, certain other features of 

 great interest made themselves evident during our period. 



