230 



SCIENTIFIC THOUGHT. 



and botany tell us, the use of the microscope had 

 made little or no progress 1 during the eighteenth 

 century : the study of structures and tissues had lost 

 interest in comparison with the study of the physi- 

 ological functions of the parts of plants and the organs 

 of animals, which had been respectively furthered by 

 26. Hales in England and by Haller in Germany. 2 Our 



Its improve- 

 ment, century thus found the morphological studies of the 



imperceptibly small in a very backward state : it had 

 to improve the instrument for its research pari passu 

 with this research itself. 3 But it has been truly re- 

 marked that the increased use of the microscope 

 necessitated likewise a mental training in the Inter- 

 pretations and delineations of what was observed 

 through it. " By fortifying the eye with the micro- 



1 "So long as, in consequence of 

 the imperfections of optical instru- 

 ments, deceptive images existed, 

 and, for instance, all microscopical 

 structures appeared as composed of 

 rows of beads, the explanation of 

 what was seen stood under the in- 

 fluence of deceptions, which were 

 only gradually recognised as such " 

 (Carus, 'Gesch. d. Zool.,' p. 629). 

 Compare also what Sachs says 

 (Gesch. d. Bot., p. 241). 



2 ' ' The characteristic feature of 

 that period lay in this, that the 

 examination of the finer structure 

 is always mixed up with reflections 

 on the functions of elementary 

 organs, so that anatomy and phy- 

 siology always support each other, 

 but also, in consequence of their 

 imperfect state, do each other in- 

 jury" (Sachs, loc. cit., p. 240). 

 Similarly Carus (loc. cit., p. 567), 

 " Through the progress which phy- 

 siology made, thanks to Haller's 

 activity, zootomical investigations 



took a direction which brought 

 them into complete dependence on 

 physiology, . . . and retarded the 

 progress of zoology by diverting at- 

 tention from its primary object 

 the exposition of animal forms and 

 their differences." 



3 As late as 1827 Aug. Pyrame 

 de Candolle could still write (' Or- 

 ganographie vege'tale,' vol. i. p. 7), 

 " De nos jours, MM. Mirbel, Link, 

 Treviranus, Sprengel, Rudolphi, 

 Kieser, Dutrochet, et Amici ont 

 public" des recherches tres dedicates 

 sur le tissu vegetal, et les ont ac- 

 compagnees de figures nombreuses 

 et soignees ; mais la necessite d'em- 

 ployer continuellement dans ces 

 recherches un instrument aussi 

 difficile a bien manier que Test le 

 microscope compose, fait que Emigre" 

 1'habilete" de ces observateurs, 1'anat- 

 omie delicate des ve"ge"taux estencore 

 . . . d'une incertitude de"sespe"rante 

 pour les amis de la ve"rite"." 



