206 PHYSIOLOGY. 



powerful in disordering the system ; but there are certainly also 

 many thrown in that have no effect at all : for, not to mention 

 the various precautions which nature has taken to prevent their 

 reaching the mass of blood, I think it is only necessary to ob- 

 serve, that even when in the mass of blood, they are rendered 

 innocent, by their being joined with, and diffused in the sero- 

 sity, and with it soon thrown out by one or other of the excre- 

 tions ; so that some of the most acrid, as mercury and can- 

 tharides, show their effects only in the secretory or excretory 

 organs. 



" Upon the whole of this subject, therefore, I would conclude, 

 that the supposition of an acrimony as the cause of diseases, has 

 been too frequently admitted in our modern pathology ; and 

 that it ought not to be admitted, unless when the causes and ex- 

 istence of it are well ascertained. 



" To conclude, I will not deny that the state of the fluids 

 may have a share in distinguishing the different states of the 

 body both in health and in sickness : but at the same time I 

 must maintain, that we know little of the manner in which it 

 may have this effect ; that our theory of the human fluids is 

 still very incomplete and imperfect ; that, while in this condi- 

 tion, it has been employed too rashly and too largely in every 

 part of the system of physic ; and that we have little tempta- 

 tion to do this, as it is highly probable that the state of the 

 fluids depends very much upon other circumstances of the con- 

 stitution, which are more fundamental, and more powerful in 

 determining the several conditions of it." M. M. 



CHAP. III. OF SECRETION. 



CCLXXV. After thus considering the parts of the mass 

 contained in the red vessels, we must next consider the several 

 fluids which appear in the other parts of the body. 



CCLXXVI. All of these we suppose to be derived from 

 the common mass, as they appear in vessels continuous with 

 those of the common mass, and as their appearance ceases when 

 the communication of the vessels containing them, with the 

 sanguiferous vessels, is any how interrupted. 



CCLXXVII. The fluids thus derived from the common 



