Physiological Researches on Life and Death

by Xavier Bichat

A recapitulation of these properties may be seen in the following table:

Properties.
	Classes.		Genera.		Species.		Varieties.
		{		{	1st Animal
			1st Sensibility—
					2d Organic
		{
	1st Vital—			{	1st Animal
		{	2d Contractility—			{	1st Sensible
					2d Organic—
							2d Insensible
		{	1st Extensibility
	2d of Texture—
			2d Contractility

I have not inserted in this table that modification of motion, which takes place in the iris, the corpora cavernosa, &c. a motion, which precedes the influx of the blood, and which is not in such way occasioned, neither have I mentioned the dilatation of the heart,[39] and in a word that species of active and vital excitability, of which some parts appear to be susceptible, and my reason for this neglect, although I recognise the reality of the modification, is my want of clear and precise ideas on the subject.

From the properties, which I have now explained, are derived all the functions, all the phenomena, which are exemplified in the living œconomy. There is not one, which may not be traced to them after a strict analysis, in the same manner as in the phenomena of physics we recur to the properties of attraction, elasticity, &c.

Wherever the vital properties are in action, there is a disengagement, and a loss of caloric peculiar to the animal, which compose for him a temperature independent of the medium in which he lives. The word caloricity will hardly serve for the expression of this fact, which is a general effect of the two great vital powers in a state of action, and not produced by any especial faculty distinct from them. We do not make use of the words, digestibility, or respirability, because digestion and respiration are the results of functions derived from the common laws of the system.

For the same reason the digestive power of Grimaud suggests an inaccurate idea. The assimilation of heterogeneous substances to our organs, is not the effect of any peculiar power. The same may be said of the different principles admitted by a number of authors, who have attributed to results and functions denominations expressive of laws, and vital properties.

The proper life of each organ is composed of the different modifications, to which are submitted in each of them the vital sensibilities and mobilities, modifications, which invariably are productive of others in the circulation and temperature of the organ. Let it be noticed however, that each organ independently of the general sensibility, mobility, temperature, and circulation of the body, has a particular mode of sensation and heat, together with a capillary circulation, which being withdrawn from the influence of the heart, receives the influence only of the tonic action of the part.[40] But we may pass over a point so frequently and sufficiently discussed by other authors.

Let it here be understood that I offer what I have said on the subject of the vital powers, only as a simple view of the different modifications, which they experience in the two lives. These detached ideas will in a short time form the basis of a more extensive work.

Neither have I recapitulated the different divisions of the vital powers, which have been adopted by authors; the reader will find them in their works, and will easily perceive the differences, which distinguish them from those, which I have adopted. I shall only observe that were these divisions clear and precise, did they suggest to all the same meaning, we should not have to regret in the writings of Haller, Lecat, Wyth, Haen, and all the physicians of Montpellier, a number of disputes of no importance to the interest of science, and surely fatiguing to the student.

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