14 GENERAL PHYSIOLOGY. 



etc., make up the true condition of physiology, as well as of 

 the science of life, or science of living matter. An era of 

 complete darkness, that is, of pure hypotheses, followed the 

 time of Galen, who had with difficulty enounced this theory. 1 

 Neither Descartes, Newton, nor Boerhaave had any thing to 

 do with physiology ; they simply applied the facts of mecha- 

 nism and physics to living beings. 



Glisson (in 1672) was the first to suggest the word " irri- 

 tability," which he considered a characteristic property of 

 living beings ; a property determining the organic move- 

 ments, and which is set in motion by causes either from 

 without or from within, which he calls irritant causes. But 

 these theories by which Glisson characterized life in a manner 

 so remarkable for his time, passed unnoticed by his contempo- 

 raries; and we see with Stahl (1708), and then with Barthcz, 

 the teaching of the animists and the vitalists coincide almost 

 exactly with the ancient theories of a fundamental force 

 rj), upon which depend all the manifestations of life. 2 



1 The ancients, among them Hippocrates, Plato, and Aristotle, 

 being almost entirely without observations or experiments, were 

 busied with the essence of life, founded on pure hypothesis, char- 

 acterized generally by their belief in a principle of life distinct 

 from matter (-^v^ of Aristotle), hypotheses which were soon to 

 reappear under the name of animism and vitalism. Galen, turn- 

 ing his attention to anatomy, rejected the purely speculative doc- 

 trines, but still his physiology was only a logical inference from 

 anatomy, for, wisely keeping within certain bounds furnished by 

 his observation, he sought only the part played by the different 

 organs (de usu partium) . This should be the true spirit to preside 

 over the study of physiology. Under such an idea Galen deserves 

 indeed the title of " The Father of Physiology." The physiolo- 

 gists of the present time add only what has been obtained by means 

 of investigation, and consequently obtain results far different. Being 

 able to study the organs only macro-graphically, Galen was obliged 

 to look upon their functions simply as nearly mechanical; now the 

 microscope reveals to us the globule, which, in the order of things, 

 we can consider as the strictly vital element. Studying the prop- 

 erties and functions of these cells in the same way that Galeu 

 studied those of the organs, we may perhaps attain the true knowl- 

 edge of vital phenomena, without having recourse to hypotheses: 

 life will be really represented by the cell reacting under the influ- 

 ence of excitauts. An organ, even the whole organism, will be a 

 union of cells, as an association is a union of individuals. (Vide 

 Cl. Bernard, " Legons sur les Proprieties des Tissus Vivants." 

 1866.) 



2 Stahl would not admit that living matter had vital activity or 



