PHYSIOLOGY. 11 



to depend upon the difference of the mixture, aggregation, or 

 organization of the solid. 



X. The matter of the simple solid every where, except in the 

 bones, appears to be an homogeneous aggregate ; and there is 

 no proper evidence of its being formed of certain parts naturally 

 discrete and incoherent, which are cemented by others of a dif- 

 ferent nature. 



XI. Of the simple solid considered as an homogeneous 

 aggregate, the integrant parts are a milt, which seems to be 

 nearly of the same kind in all the different parts of the human 

 body, and perhaps in most of the parts of every animal. So far 

 as we yet know, the variety of it is very inconsiderable. 



XII. This, which may be called the ANIMAL MIXT, is found, 

 by chemical experiment, to be considerably different from every 

 kind of vegetable or fossil matter ; but the same experiments 

 hardly teach us any thing exact or useful with respect to the 

 constituent parts of this mixt. 



XIII. The only particular relative to this which we exactly 

 know, is, that the animal mixt is formed of water, and of some 

 other matter concreting with it ; that, on different occasions, the 

 state of it is varied by the proportion which the water bears to 

 the other concreting matter ; and that, especially by a different 

 proportion in this respect, the simple solid differs in its force of 

 cohesion, flexibility, and elasticity (VIII.) 



XIV. The proportion of water to the other matter in the 

 animal mixt of different persons, seems to depend, in the first 

 place, upon the nature of the original stamina in each ; as the 

 different state of simple solids, which appears early to distin- 

 guish sex and temperament, continues respectively the same 

 through the whole of life, even though the different persons are 

 under the same external circumstances. 



XV. But, in every particular person, that proportion is 

 constantly changed by the progress of life ; and this happens 

 more or less as other causes concur. 



XVI. The causes that can affect the mixture of the simple 

 solid, are either the state of the nutritious fluid conveyed by the 

 ordinary channels, or some matters from without insinuated into 

 the solid. 



XVII. The state of the nutritious fluid may be varied by 



