PRESIDENTIAL ADDRESS. 653 
Disintegration and readjustment due to altered outlook are familiar pro- 
cesses. Histology, parting company with organography to serve physiology, 
is now an independent study, one of whose branches occasionally declines to 
accept any doctrine unconfirmed by cytological methods. The study of 
problems relating to nutrition and reproduction has been considered the 
especial task of physiology. Now, the chemist at times claims the problems of 
nutrition as part of his field, and we look for advances in our knowledge of 
reproductive problems to the cytologist and the student of genetics. These 
instances are adduced from without because relative exemption from disinte- 
gration is a distinctive feature of systematic study. The two-sided task of 
the systematist is to provide a census of the known forms of plant life and to 
explain the relationships of these forms to each other. The work on one side 
is mainly descriptive, on the other mainly taxonomic, but the two are so 
interdependent, and their operations so intimately blended, that it is difficult 
to treat them apart. Reorientation in botanical study has led to seismic dis- 
turbances in the taxonomic field, but the materials supplied by descriptive 
work have remained unaffected, and therefore have been ready for use in the 
repair or reconstruction of shattered ‘ systems.’ 
The exemption from radical change in method, which marks systematic 
work, is due to those characteristics that expose it to the charges of discourag- 
ing originality and of calling only for technical skill. It also largely explains 
why systematic study, especially on the descriptive side, is not attractive to 
minds disposed towards experimental inquiry. The labour involved is as 
exacting, accurate record and balanced judgment are as necessary, in descrip- 
tive as in experimental research. ‘ A skill that is not to be acquired by random 
study at spare moments’ is as essential in descriptive as in other work, while 
the relief that variation in method affords is precluded. Increased experi- 
ence, here as elsewhere, leads to more satisfactory results, but without, in this 
case, mitigating the toil of securing them. The testing of theories, often an 
inspiring task in experimental research, in the descriptive field retards pro 
gress. But if in descriptive work imagination and the spirit of adventure are 
undesirable, these qualities are not inhibited by systematic study as a whole. 
Imagination is legitimate and useful in the taxonomic field, and in another 
line of activity—the acquisition of the material on which descriptive work is 
based—the spirit of adventure is essential to success. 
The untravelled descriptive worker is not without consolations. His work 
is as necessary to botany as that of the cartographer to geography, or the 
grammarian to literature. His results are means to the ends that others have 
in view. If these results often appeal to coming rather than to contemporary 
workers, the descriptive writer is at least largely spared the doubtful benefit 
of immediate appreciation. He can pursue his studies unaffected by any con- 
siderations save those of adding to the sum of human knowledge and of bring- 
ing a necessary task appreciably nearer completion. In descriptive study it is 
the work rather than the personality of the worker that tells. Yet the work is 
not without human interest, because systematic writings rarely fail to reflect 
the character of the writers. The intimate knowledge of descriptive treatises, 
which floristic or monographic study entails, usually leads to mental estimates 
of the actual authors. The evidence on which these estimates depend is un- 
wittingly given and unconsciously appreciated. But its value is not thereby 
diminished, and estimates so formed may prove useful checks on contemporary 
judgments. 
The descriptive worker as a rule makes his work ‘ the primary business of 
his life, which he studies and practises as if nothing else in the world 
mattered.’ But he does not hold aloof from those éngaged in other lines of 
botanical activity. His evidence is mainly obtained from organography and 
organogeny; but, just because his results are for the use of others, the 
descriptive botanist has to keep abreast of all that is done in every branch of 
his science. New weapons are constantly being forged, and not in morpho- 
