Some Aceount of M. Blchat's Theory ojLl/e. 175 



life, tlie organs have in the first place a sort of sensibility* or 

 perception, by which they become acquainted with the pre- 

 sence and qualities of the substances applied to them ; this is 

 the organic sensihilitij ; they have then a property by which 

 they react upon these substances, and excite in them motion ; 

 this is the organic contractilitij. It has two modifications. 

 1. Where the contraction is insensible, as in the exhalants, 

 capillaries, secreting vessels. 2. Where it is sensible, as in 

 the heart, the stomach, the intestines, and these are called re- 

 spectively, the insensible, and the sensible, organic contractility. 

 In the organs of the animal life, there is also a sensibility, by 

 which they are not only made capable of receiving the im- 

 pression of an object and its qualities, but of transmitting that 

 impression to the conmion sensorium; and a contractility, 

 which not only renders a part capable of contracting, but is in 

 the exercise of its power under the entire control and direc- 

 tion of the brain. These properties are called the animal 

 sensibility and the animal contractility. 



But the principal and most important feature in the physio- 

 logical system of Bichat, is the complete, and entire, and ex- 

 clusive explanation of all the phaenomena of the living system 

 upon the principles of Vitality alone. Former physiologists 

 have not always kept this distinctly in view ; they have not 

 invariably recognised the principle, that the living system is 

 in a certain sense insulated with regard to other matter; th?t 

 it is governed by a set of laws essentially its oion, peculiar to 

 itself. The human body has been regarded, too often, as a 

 mass of matter, organized to be sure, but yet under the direc- 

 tion of physical laws, and the performance of its functions has 

 been ascribed to the powers of inoiganic matter. Hence phy- 

 siology has generally been somewhat tinctured by the favourite 

 science of the age, with some of its notions. In the days of 

 mechanical })hilosophv, the functions were explained as much 

 as possible by the laws of mechanics. The force of every 

 muscle was calculated to a grain, the velocity and momentum 

 of the blood were sujiposed to produce the motions of the 

 living fibre, and the fibre to be so constituted as to vibrate 

 like the chords of an instrument: the stomach acted on the 

 food like a pair of mill-stones, the chyle was absoi'bcd from 

 the intestines by the power of capillary attraction, and animal 

 heat produced by the mutual attrition of the fluids and solids. 

 So witli tiie chemists, the human system was no less than a 

 chemical laboratory. The stomach was a crucible, a retort, 



• Rc3pectin<; tlie ambiguous use of this word, see p. 116, andZ)«w«(MM 

 of Purify, ii. 48G. 



