158 



holding a relation liable to catenate changes with contiguous or dis- 

 tant ones of the same kind ; and being in this manner united with 

 the textures, participate, according to their own relations, in the 

 changes which the textures might be made to undergo. 



27. 4th, The motions of the mechanical alliances can affect 

 the spirit only in the way of re-agency; and the supposed instances 

 of this are rather of a doubtful nature. Thus it is one of the effects 

 of that state of the spirit constituting fever, to accelerate the move- 

 ments of the heart, and to produce a rapid circulation. The fluids, 

 in this case, having an increased impetus, may pass into channels 

 which before received those only of another kind, and in this way, 

 from the relation spoken of between the spirit and the chymical 

 nature of the fluids, the former in these places may be affected ; or 

 the process of the material aggregation mentioned in the article ou 

 Growth, may be impeded by destroying a balance which we have 

 supposed to exist between the motion of particles destined for aggre- 

 gation, and that power of the spirit by which the place of particles 

 is fixed and their impulse of motion counteracted (which agrees 

 with the reduction of bulk consequent upon fevers, though I will 

 hardly call it an explanation of this circumstance). 



28. It has been common to consider this rapidity of circulation 

 as the cause, rather than the effect of the febrile state; and in this 

 view the cure is designed by diminishing the action of the heart ; 

 and this design succeeds because the action of the heart is diminished 

 by means which first influence the state of its moving powers, re- 

 storing them from the modified to their natural state. But how far 

 the rapid or slow motions of the fluids may be capable of influencing 

 the state of the spirit it may be difficult to decide. Indeed the 

 most that we can do with the facts which we possess is to allow that 

 some sort of relation of this kind might subsist; though I see many 

 indications by which even the existence, to say nothing about the 

 assigned phenomena, of the relation, may be brought under doubts. 

 The leading particulars of the relation comprehended in the pre- 

 ceding discussions may be summed up as follows : 



1. The spirit produces the chymical materials both of the fluids 

 and of the solids ; by which is meant that materials are combined or 

 aggregated by the agency of the spirit, which, without this agency, 

 would be neither combined nor aggregated. 



2. The spirit is directly related with the chymicals, both as the 

 spirit is liable to influence and to be influenced by the chymicals. 



3. The influence of the spirit on the chymicals secures their 

 conformity to it, so that, by a natural and healthy condition of the 

 spirit, the chymicals concur for the well-being of the animal; and 

 theirs is a forced concurrence, since no animal condition of them 

 would take place but for the agency of the spirit upon them; and 

 in: the spontaneous changes of the chymicals, as these changes are 

 peculiar to the living state, so it is to be inferred that they would 

 not fake place but for a previous modification of the spirit in some 

 or other of its seats, the dmuicub of themselves tending invariably 



