September 20, 1895.] 



SCIENCE. 



361 



element of interest not inherent in those of 

 other departments of botanical science. 

 They embrace the dynamical property of 

 motion, which never fails to exercise a fas- 

 cination over the human mind . Physiology, 

 in fact, deals with what plants do, their 

 methods of activity, their behavior ; while 

 the other divisions of botany treat of what 

 plants are, or have been, their form, struc- 

 ture, and relation of parts. The one is the 

 study of the organic machine in action, and 

 the other the contemplation of its compo- 

 nent members. 



Movement in plants does not attain the 

 rapidity exhibited by animals. Some move- 

 ments in both cases are ultra-visual, as the 

 translocation of molecules in metabolism, 

 the diffusion of gases, and in plants es- 

 pecially the flow of liquids. In plants even 

 the movements of the organs are compara- 

 tively slow. While the leaves of the sen- 

 sitive plant telegraph plant, and Venus's 

 fly-trap and the petals of certain orchids 

 excite the wonder of the casual beholder, 

 most plant organs move too slowly to be 

 readily detected without mechanical mag- 

 nification. This does not prove a detraction 

 to the interest of the subject, however, as it 

 has led to the invention of ingenious and 

 complicated machines, whose numerous 

 wheels and bands inspire a sense of im- 

 portance, particularly appealing to a large 

 class of persons in this age of machinery, 

 and constituting an element in securing fa- 

 vorable attention from the public, while it 

 adds a charm to the work of the investi- 

 gator, rivalling that of the microscope. It 

 is yet but the dawning of day for the dis- 

 play of mechanical contrivances as aids to 

 botanical research, and the future gives 

 promise of notable achievements. The 

 names of Barnes, Anderson, Stevens, Stone, 

 Golden, Thomas, Frost and Arthur at 

 present are representative of the American 

 inventive spirit in botanj^. The most per- 

 fect and interesting pieces of apparatus yet 



turned out by them embrace Frost's and 

 Golden's auxanometers for recording the 

 increase in length or thickness of growing 

 organs, Thomas's apparatus for recording 

 the variation in pressure of sap resulting 

 from root action, Anderson's automatic 

 balance for registering the rate and amount 

 of change in the weight of an object used 

 in studying transpiration and growth, and 

 Arthur's clinostat for neutralizing the ac- 

 tion of gravity and light, and his centrifu- 

 gal apparatus for substituting mechanical 

 force for that of gravity. 



"While having in mind the public interest 

 in our science, it may be well to notice the 

 very small basis of information on which 

 this interest is founded. Only the vaguest 

 notions are current regarding the nutrition, 

 of plants, the uses of the leaves, the move- 

 ments of sap, the purposes of color, and the 

 means by which new positions are assumed. 

 This ignorance is primarily due, of course, 

 to the some cause which has so long delayed 

 the development of the science upon the 

 technical side — the fact that almost nothing 

 can be leai-ned of the functions of plants 

 from direct observation. In regard to the 

 physiology of animals, even the lowest, 

 much may be inferred by observing their 

 behavior and analyzing the phenomena 

 from the human standjjoint, but there are 

 no obvious similarities between plants and 

 the higher animals, and it is necessary to 

 resort to careful experimentation and pro- 

 found study to arrive at a fair understand- 

 ing of the vital actions of plants. Physiol- 

 ogy is an experimental science, and the 

 public must perforce derive its knowledge 

 second hand without much opportunity of 

 verification. It must be admitted that, al- 

 though a view of this portion of the res 

 publica naturae has its fascination, yet the 

 attainment of vantage ground for the sur- 

 vey is necessarily difficult and slow. 



The term public, when used iu connection 

 with vegetable physiology, needs to be con- 



