MODERN BIOLOGY 349 



to the anatomical nature of the dead body. Life consists rather in certain 

 qualities, which the living tissues possess and which are not found in inani- 

 mate nature. Here Bichat takes as his starting-point Haller's previously- 

 mentioned theories of irritability and sensibility and he develops them 

 further, expressing great appreciation of Haller, who, to his mind, had a 

 far more correct view of life than Stahl. According to Bichat, sensibility 

 is the characteristic quality of the nervous system; the muscular system dis- 

 plays a quality that he calls contractility; this has different characteristics 

 in different organs and should not be confused with the tensibility that the 

 tissues possess independently of life. But life manifests itself not only in these 

 qualities, but in still another phenomenon, unknown in inanimate nature; 

 this is called sympathy and expresses itself in the effect that the vital func- 

 tions of the various organs have upon one another in conditions of sickness 

 and health. Bichat made serious attempts to ascertain the nature of these 

 vital phenomena by experimenting with living organs under various con- 

 ditions. Thus he tried to analyse especially muscular contractility and dis- 

 tinguishes several categories thereof — namely, he holds that the muscle 

 comes into action: (i) as the result of impulses from the brain received 

 through the nerves — that is, normal contractility; it ceases if the nerve is 

 severed; (i) through chemical or physical influences — that is, organic and 

 sensible contractility or irritability; it ceases if the muscle is deadened (e.g., 

 by opium); (3) through the fluids which the vascular systems convey to the 

 muscle and which distend its minutest parts — that is, passive contractility 

 or tonicity; it ceases as a result of death; (4) finally, the muscle contracts on 

 being severed — that is, the contractility of tissue itself, which only ceases 

 as a result of putrefaction. Of sensibility he distinguishes two categories — 

 namely, "organic," which consists in the power of receiving an impression, 

 and "animal," which not only receives the impression, but conveys it 

 farther to a common centre and is thus a higher category of the previous one. 



Organic and anbnal life 

 The contrasted ideas, organic and animal, frequently referred to above, play 

 an important part in Bichat's explanation of life. "Organic" are vegetable life 

 and the unconscious life of animals; "animal" are the functions in animals 

 that are controlled by the will of the individual and are consequently the 

 more developed the higher the life is. Even in modern times one sometimes 

 differentiates between animal organs, among which are included especially 

 the nervous system and the motive organs, and the vegetative, among which 

 are included the digestive, circulatory, respiratory, and excretal organs. 

 Bichat, however, carries this differentiation to most absurd extremes when 

 he consistently speaks of "the two lives," the animal and the organic, and 

 assures us that the former's organs are always symmetrical and the latter's 

 unsymmetrical, much labour being spent on trying to prove that lungs and 



