442 BIOLOGY IN RELATION TO OTHER NATURAL SCIENCES. 



ized structures are built up of those i^articles of liviug substauce whicli 

 we uow call cells, and recognize as the seats aud sources of every kind 

 of vital activity. Hugo Mold, workiug in another direction, had given 

 the name "protoplasm" to a certain hyaline substance which forms 

 the lining of the cells of plants, though no one as yet knew that it was 

 the essential constituent of all living structures — the basis of life no 

 less in animals than in plants. And, finally, a new branch of study, 

 histology, founded on observations which the microscope had for the 

 first time rendered possible, had come into existence. Bowman, one of 

 the earliest and most successful cultivators of this new science, called 

 it physiological anatomy,* and justified the title by the very important 

 inferences as to the secreting function of epithelial cells and as to the 

 nature of muscular co'ntractiou, which he deduced from his admirable 

 anatomical researches. From structure to function, from nucroscopical 

 observation to physiological experiment, the transition was natural. 

 Anatomy was able to answer some questions, but asked many more. 

 Fifty years ago physiologists had microscoiies but had no hiboratories. 

 English physiologists, l^owman, Paget, Sharpey, were at the same tin\e 

 anatomists, and in Berlin, Johannes Miiller, along with anatomy and 

 physiology, taught couiparati ve anatomy and pathology. But soon that 

 sj)ecialization which, however nuicli we may regret its necessity, is an 

 essential concomitant of progress, became more and more inevitable. 

 The structural conditions on which the processes of life depend had 

 become, if not known, at least accessible to investigation; but very 

 little indeed had been ascertained of the nature of the processes them- 

 selves, so little indeed, that if at this moment we could blot from the 

 records of physiology the whole of the information which had been 

 acquired, say in 1840, the loss would be diflicult to trace, not that the 

 previously-known facts were of little value, but because every fact of 

 moment has since been subjected to experimental verification. It is 

 for this reason that, without any hesitation, we accord to 3Iiiller and to 

 his successors, Briicke, du Bois-Eeymond, Helmholtz, who were his 

 pupils, and Ludwig, in Germany, and to Claude Bernard t in France, 

 the title of founders of our science. For it is the work which they began 

 at that remarkable time (1840-1855), and which is now being carried 

 on by their pupils or their pupils' pupils in England, America, France, 

 Germany, Denmark, Sweden, Italy, and even in that youngest contribu- 

 tor to the advancement of science, Japan, that i)hysio]ogv has been 

 gradually built up to whatever completeness it has at present attained. 

 What were the conditions that brought about this great advance 

 which coincided with the middle of the century? There is but little 



*The first part of the Pln/siolotjicul Analonnj jippeared in TS13. It was concludeil 

 in 185fi. 



tit is worthy of note that these five distinguished men were merely contempora- 

 ries; Ludwig graduated in 1889; Bernard in 1S43; the other three between those 

 dates. Three survive — Helmholtz, Ludwig, du I5ois-Reymoud. 



