220 PHYSIOLOGY. 



Choleric ; that is, of more strength than in the sanguine, and of 

 more irritability than in the melancholic. It is possible also, 

 that there may occur a simple solid more dense than usual in 

 the sanguine, and at the same time, from a more humid state, of 

 greater flexibility than in the melancholic ; and if, along with 

 these, there may be an analogous state of the medullary fibre, 

 of less mobility and elasticity in proportion to the density, we 

 shall then have that temperament which the ancients expressed 

 by the title of Phlegmatic ; that is, with less sensibility and irri- 

 tability, but with more strength and steadiness than hi the san- 

 guine, and at the same time with more laxity and more muta- 

 bility than in the melancholic. 



In the whole of this discussion, we have considered the state 

 of the nervous power as chiefly modifying the temperaments 

 of men ; and more readily enter into this supposition, because 

 we presume the state of the nervous power to be almost al- 

 ways attended by a corresponding state of the simple solid, and 

 that both these together pretty constantly modify the state of 

 the fluids, both with respect to their quality, their proportion, 

 and distribution. 



Of these latter circumstances, however, constantly following 

 the state of the simple solids and of the nervous power, I am 

 by no means certain. As we observe, that at different periods 

 of life there is a difference between the arteries and the veins 

 as to the circumstances of density and capacity, so it is possi- 

 ble that some difference in these respects may be established in 

 the original stamina, and may therefore, in some degree, run 

 throughout the whole of life, and thus vary the state of the 

 fluids. It is also possible, that there may be conditions of the 

 original stamina determining a difference in the strength and ac- 

 tivity of the heart with respect to the capacity of the blood-ves- 

 sels ; or, on the other hand, the state of the heart being given, 

 there may be a difference in the density and resistance of the 

 sanguiferous system. In all these cases, there may arise a dif- 

 ference in the quality, proportion, and distribution of the fluids, 

 and, thereby, a further variety in the temperaments of men ; and 

 thus, perhaps, we may account for the difference of stature, 

 bulk, and proportion, of the several parts of the body in differ- 

 ent persons. 



