OF THE GLOBULE OR CELL. 15 



With Haller reappears Glisson's expression, u irritability." 

 Though but theoretically showing that irritability was a 

 property of living matter, Haller experimented directly 

 upon living animals; his vivisections gave him an oppor- 

 tunity especially of studying muscles, and he applied the 

 word " irritability " particularly to the muscular system ; if 

 he went no farther, still he used the experimental method 

 of study, and the theory of irritability took its definite posi- 

 tion in science. Brown (1780) generalized this term under 

 the special names of " instability ' and of " incitants " (incita- 

 menta), giving a name to that property possessed by living 

 matter, of performing its functions under the influence of 

 external causes, without the intervention of any . distinct 

 principle of the organism. 1 Tiedemann carried out the same 

 principle by substituting for the words " incitants," " incita- 

 bility," those of " excitability," and " excitants." But yet, if 

 the words " excitability," " incitability," or "irritability," in 

 spite of their variety, express a real property, the value and 

 limitation of the words " living matter," to which these 

 authors attribute the property, is not precisely defined. 

 Moreover, they do not agree in regard to its definition. 

 Haller seems to consider that the muscle almost alone is 

 irritable, whilst Brown considers all the solid portions of the 

 organism are incitable; but not so with the liquids. And 

 again, Tiedemann would allow excitability to both liquids 

 and solids. This confusion existed even to the time when 

 general anatomy was founded upon histology, as revealed by 

 the microscope. Now the cell must be recognized as the primi- 

 tive element of the organism. We have seen that it alone 

 is the seat of vital phenomena, that it alone is excitable in 

 pome tissues ; as, for instance, the muscles, which, being de- 

 irritability, and supposed a vital force, independent of organic 

 elements, an immaterial substance, the soul (not to be confounded, 

 however, with the soul of philosophers and theologians, which is 

 not the same as that which is called ' * soul " by physiologists) , which 

 is endowed with absolute free-will, and presides alone over the 

 functional movements of our organs. Such is the animism of 

 Stahl, which later reappears in several schools under the name of 

 vitalism. The vitalises substitute simply for the word "soul" 

 " vital force," or " vital principle," a hidden quality, a funda- 

 mental force w r hence spring all the manifestations of life. 



1 The whole medicine of Broussais is but a theory of incitants 

 imported from physiology, and applied to pathology. These are 

 pathological incitants, and all diseases come from irritations. For 

 details vide Cl. Bernard, " Propriete des Tissus Vivants." 



