158 The Anatomy of Plants BOOKII 



A. Braun, Cohn, Unger, and von Mohl, but its importance 

 was not fully realized till Max Schulze, in 1863, demon- 

 strated its identity with the sarcode of the animal world, 

 and so placed animals and plants upon the same plane 

 as living organisms, and made possible the researches upon 

 a common physiology which bulked so large towards the 

 end of the century, giving rise indeed to a new science 

 Cytology, or the study of the cell. 



Anatomical researches had been industriously followed 

 by many botanists during the years before 1860 indeed, 

 they were being pursued with great assiduity then. A very 

 great advance had been made by Naegeli's magnificent 

 generalization as to the intimate structure of organized 

 substances, a work which explained many till then obscure 

 observations, and threw a great deal of light upon many 

 problems at the moment under consideration. Though 

 Naegeli's conception as he left it did not stand the test of 

 the critical examination brought to bear upon it during 

 the two succeeding decades, it served a most useful purpose 

 in stimulating research. Modified by the results of criticism 

 and in part replaced by other hypotheses, it still stands 

 out as a conception almost of genius, a landmark in the 

 survey of the opinion of the time. 



If we turn to examine the general conception of anatomy 

 in 1860, we find that there had been a good deal of develop- 

 ment of the cell theory since its original promulgation. 

 So far as the vegetable organism was concerned, however, 

 the conception of protoplasm had not reached its proper 

 importance. The cell wall, recognized later as only sub- 

 ordinate, was the central object of investigation. The 

 work of observers still led to views of structure based upon 

 the independence, or, perhaps preferably the isolation, of 

 the cell. The idea of intercommunication of cells at all 

 was confined to sieve tubes, which had been discovered by 

 Hartig long before, but whose perforation was still a subject 



