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demonstrated facts to the general store of knowledge ; in fact, 

 for a time the additions to morphological information very much 

 outran the development of the physiological side, though the 

 latter had had a rational beginning at a prior date. The morpho- 

 logical development depended in the first instance upon the 

 understanding that the cell with its living protoplast, and usually 

 with a wall, constituted a not further divisible morphological unit 

 of living organisms ; that every cell must have arisen from a pre- 

 existing one ; and finally, that all but the lower organisms are 

 composed of thousands of these cells differentiated into distinct 

 tissues. One of the most important figures in this advance of 

 botany from Schleiden's time was Naegeli, who brought to bear 

 a powerful intellect on many of the fundamental concepts both 

 of morphology and physiology. Of the many questions dealt 

 with by him, that of the ultimate structure of organized substance 

 was perhaps the most far-reaching ; and to-day, despite its limita- 

 tions, his Micellar Hypothesis is the most stimulating of any of 

 the theories which have been developed regarding this subject. 

 The other milestone of progress was Darwin's " Origin of 

 Species " already referred to. Entirely aside from the particular 

 question involved in that work, its importance lies in the fact that 

 it fought the battle and won the victory for the inductive method 

 of reasoning as applied to biological science. Previous to the 

 awakening of botany, due to these and related causes, a botanist 

 usually covered the whole field of his science and had the right 

 to consider himself a specialist in all branches of botany. The 

 rapid accumulation of facts soon demanded, however, a segrega- 

 tion of different lines of work. Thus arose the divisions of 

 botanical activity, which, for our purposes, may be classed under 

 three heads. First, the taxonomic, or as more commonly called 

 the systematic side, which has to do with the classification, mainly 

 as established by gross morphology. Second, the morphological 

 field, which concerns itself with the outward and inward form and 

 structure and the development thereof, which may or may not 

 have direct relation with taxonomic work. Third, there is the 

 domain of physiology, which treats of function. As Professor 

 Wilson has pointed out, there are really but two divisions Or 



