November 11, 1904.] 



SCIENCE. 



623 



dent everywhei-e. Physiology and chem- 

 istry have long possessed common terri- 

 tory; plant morphology and physiology 

 have now found no barrier between them. 

 This simply means that so long as we deal 

 with the most external phenomena oiir sub- 

 jects seem as distinct from one another 

 as do tlie branches of a tree ; but when we 

 approach the fundamentals we find our- 

 selves coming together, as the branches 

 merge into the trunk. The history of 

 botany, beginning with taxonomy, has been 

 a history that began with the tips of the 

 branches and has proceeded in converging 

 lines towards the common trunk. The 

 fundamental unity of the whole science, 

 in fact, of biological science, however 

 numerous the branches may be, is becom- 

 ing more and more conspicuous. Already 

 the old lines of classification have become 

 confused, and one looking through any 

 recent list of papers finds it impossible to 

 classify them in terms of the old divisions. 

 Investigators are now to be distinguished 

 by particular groups of problems in con- 

 nection with particular material, and all 

 problems lead back to the same funda- 

 mental conceptions. In other words, the 

 point of view is to be common to all investi- 

 gators, and until it is common their re- 

 sults will not reach their largest signifi- 

 cance. 



A fourth consideration is the result of 

 all this upon taxonomy. It seems clear 

 to one who was originally trained in 

 taxonomy, and who has passed through all 

 the phases of morphology described above, 

 that the conception of species has become 

 so radically changed that a reconstructed 

 taxonomy is inevitable. When the doe- 

 trine of types disappeared, and when ex- 

 perimental morphology showed the im- 

 mense possibilities of fluctuation in taxo- 

 nomic characters, the taxonomy of the past 

 was swept from its moorings. Taxonomy 

 must continue its work as a cataloguer of 



material, but to catalogue rigid concepts is 

 very different from cataloguing fluctuating 

 variations. The attempt to do the latter 

 on the old basis is being attempted in cer- 

 tain quarters, but it soon passes the limit- 

 of usefulness and sets strongly towards the 

 record of individuals. Some new basis 

 must be devised, and it must be a natural 

 and useful expression of the relationships 

 of forms as suggested by experimental 

 morphology. 



That this history of the progress of mor- 

 phology, just outlined, is a fair indication 

 of general tendencies may be illustrated 

 from plant anatomy. This subject, not 

 well differentiated from plant morphology 

 among the lower groups, has developed a 

 veiy distinct field of its own among vascu- 

 lar plants. Its early phase was that of 

 classification, in Avhich tj^pes of tissues were 

 rigidly defined. This definite catalogue 

 of tissues continued to be used after evolu- 

 tionary morphology was well under way, 

 and morphologists gradually abandoned 

 any serious consideration of it, just as they 

 had cut loose from the old taxonomy. In 

 text-books the juxtaposition of morphology 

 upon an evolutionary basis and a little 

 anatomy upon a strictly taxonomic and 

 artificial basis became very familiar. 



Recently a second phase of anatomy has 

 begTin to appear, and we find it upon an 

 evolutionary basis. Investigation has 

 passed from the study of mature tissues to 

 the study of developing tissues, and the 

 seedling is more important to the anato- 

 mist than the adult body. As in the corre- 

 sponding phase of morphology, the funda- 

 mental conception of this new phase is the 

 theory of recapitulation, and its ultimate 

 purpose is phytogeny. It views tissues as 

 morphology views organs, and is attack- 

 ing the same general problems. In so do- 

 ing it becomes a special field of morphology, 

 no more to be separated from it than are 

 morphologists who study the sporophyte to 



