29 



Not so with the truly vital extensibility , which is so manifest in certain 

 organs, as the penis and the clitoris. When excited, they become tur- 

 gid and dilated by the afflux of blood, but that effect does not depend 

 on a peculiar property, distinct from sensibility and contractility. These 

 parts dilate, their tissue stretches under the action of these two proper- 

 ties, which would occasion the same phenomenon in all other parts, if 

 their structure were similar. 



The same applies to caloricity, or that power inherent in all living be- 

 ings, of maintaining the same degree of heat, in varying temperatures*. 

 In consequence of which property, the human body preserves its tempera- 

 ture, of from thirty to forty degrees (Reaumur's scale) under the frozen 

 climate of the polar regions, as well as in the burning atmosphere of 

 the torrid zone. It is by the exercise of sensibility and of contrac- 

 tility, that is, by the exercise of the functions over which these vital 

 powers preside, that the body resists the equally destructive influence of 

 excessive heat and cold. 



If we were to admit caloricity as one of the vital properties, because, 

 according to Professor Chaussier that power of preserving a uniform 

 warmth is a very remarkable phenomenon; we might be led to suppose, 

 a distinct cause or a peculiar property to operate iu producing other phe- 

 nomena of no less importance. 



Barthez and Professor Dumas have fallen into the same error, the for- 

 mer, in wishing to establish the existence of a power of permanent siutua- 

 tion in the molecules of muscular fibres; the latter, in adding to sensibili- 

 lity and contractility a third property, which he terms the power of 

 vital resistance. Living muscles are torn with much more difficulty than 

 when dead, because the contractility which these organs possess m the 

 highest degree, is incessantly tending to preserve the contact of the mo- 

 lecules, the series of which forms the muscular fibre, and even to draw 

 them into closer connexion. This fact, which is brought forward as a 

 proof of the existence of a peculiar power, is easily explained, on the 

 principle of contractility. 



Organized and living bodies resist putrefaction, from the very circum- 

 stance of their being endowed with life. The continual motion of the 

 fluids, the re-action of the solids on the fluids, the successive and conti- 

 nual renovation of the latter, by the reception of new chyle, their constant 

 purification by means of the secretions, through which the products ani- 

 malized in excess are parted with, such are the causes which prevent the 

 putrefactive action from taking place in bodies endowed with life, not- 

 withstanding the multiplicity and the volatility of their elements. Their 

 preservation is therefore a secondary effect, and depending on the exer- 

 cise of the functions regulated by sensibility and contractility. Nature 

 is distinguished for deriving a multitude of effects from a very small 

 number of causes, it therefore shows a very imperfect acquaintance with 

 her laws to assign a separate cause to each fact. 



The separation of the chyle, which takes place in the duodenum, from 

 the admixture of the bile with the alimentary substance, the vivification 

 of the blood by respiration, the secretion of the fluids in tha conglobate 

 glands, nutrition in the organs, are so many acts of the living oeconomy, 



* See the notes on the subject of animal heat contained in the CHAPTER ON RES- 

 PIRATION. 



