218 CIRCULATING FLUIDS: 



Denis also analysed the blood of a girl, aged 27, in a similar 

 manner, and obtained corresponding resnlts from both forms of 

 blood. (Recherches, pp. 152, 153, and 250.) 



REVIEW OF THE MODIFICATIONS AND CHANGES THAT THE BLOOD 

 UNDERGOES IN THE COURSE OF THE CIRCULATION. 



Having in the previous section given my views respecting the 

 probable changes that the blood undergoes in the course of the 

 circulation, founded partly on numerous analyses of that fluid, 

 and partly on conclusions deduced from the necessary connexion 

 that exists betM^een the phenomena of secretion and of meta- 

 morphosis ; and having also endeavoured to explain the varia- 

 tions that occur in the blood of the same individual, through 

 the influence of nutrition and the secreting organs (as the liver 

 and kidneys), I beg once more to call the attention of the 

 reader to the subject under consideration. 



My views regarding the formation of the products of secretion 

 from the changes that the blood undergoes in the organism re- 

 quire a more searching investigation before confidence can be 

 placed in them. There is nothing improbable in the supposition 

 that the blood is changed in the manner that I have assumed ; 

 I can as easily conceive that the urea and bilin are formed by 

 the mutual action of the blood-corpuscles and the liquor san- 

 guinis, as that their origin is dependent upon the liquor san- 

 guinis alone ; but for reasons already communicated, there is 

 a greater degree of probability in the idea that these substances 

 are produced by the metamorphosis of the blood-corpuscles. 

 These reasons are founded more on the intimate connexion that 

 exists between the products of secretion, change of matter and 

 blood, and on the mutual adaptation and principle of compen- 

 sation in the organism of the animal body, than on the phy- 

 sical and chemical "momentum" of the circulation and of secre- 

 tion ; and the question we have now to consider is, whether in 

 the latter there is not something directly oiDposed to our views 

 respecting the metamorphosis of the blood. 



Before proceeding to these investigations, I must in the first 

 place revert to some of the points connected with this nieta- 

 morphic action. 



The first and principal object of the blood is the nutrition 



