BIOLOGY AMONG THE SCIENCES 1135 



among the most initiative and significant contributors to general 

 biology, thus stirred to increasing progress. 



The next great advance was made in the next generation, with the 

 help of improving microscopes. Almost two centuries before, various 

 observers, Hooke, Grew, and Malpighi, had so far made out the 

 building of plant structures, as showing the tiny chamber-like 

 spaces, which they therefore called "cells". But these observations 

 were not appreciated until the work of Schwann and Schleiden 

 especially led to the foundation of the "Cell-theory"; i.e. the con- 

 ception of plant and animal tissues, organs, and bodies, as built 

 up of constituent units ; and these not the mere ceU walls of the early 

 botanists, but of living substance, which may or may not have a 

 distinguishable cell wall. Magnificent use was soon made of this 

 cell- theory, with its vivid summary omnis cellula e cellula; as 

 especially by Virchow, whose Cellular Pathology soon proved the 

 beginning of a new and further advance in medical and even 

 physiological thought; since henceforth clearly bringing both into 

 correspondence, with suggestive exchange of ideas ever since. Yet 

 the concept of the cell remained too morphological ; until it was made 

 clear by Max Schultze, after Dujardin, Purkinje, and other pre- 

 cursors, that the matter of fundamental importance is its living 

 matter. Hence the term "Protoplasm"; and by and by its clear 

 popularisation, through the English-speaking world at least, by 

 Huxley, as "the physical basis of life", so expressing clearly its 

 physiological significance. This latter was most fundamentally and 

 clearly explained b}^ Claude Bernard in terms of its material and 

 energic changes; as at once continually building itself up, and yet 

 breaking itself down; the preponderance of the former being 

 expressed in growth, and in repairing the wear and tear of 

 activity. These conceptions were next made more precise by later 

 physiologists, as notably Hering and GaskeU; and with clear terms 

 accordingly — metabolism for the general process of change; and 

 anabolism and katabolism for its constructive and destructive pro- 

 cesses respectively. With this conception we are obviously getting 

 deeper than microscopic anatomy can follow, so here the field of 

 biology proper meets and gives place to that of chemistry; which, 

 as biochemistry, has ever since been making greater and greater 

 advance, as already indicated. 



Our bibliographic principle of arrangement will thus be intelli- 

 gible in outline upon each and all of our paired descending shelves, 

 for the structure and function respectively, of organism, organs, 

 tissues, cells, and protoplasm, each and every shelf and group of 

 investigations having its own precursors, initiators, and continuators. 

 With this diagram clear before us, it is seen to furnish us with a 

 memoria technica, not only useful for arranging such knowledge as 

 we can acquire, but also suggestive towards further increasing it. 



