288 



CHAR V. General Nature of Related Disease. 



1. THE production of a secondary by a primary disease 

 is accomplished by one or both of those modes of causation which 

 we have assigned to be universal, viz. by addition or abstraction 

 of constituents. The part which becomes the seat of the secon- 

 dary disease is now identified by its causes as a state of health. 

 This state is changed when the secondary disease happens changed 

 by what? by something added or something taken away; as, how- 

 ever the condition of disease always respects either exclusively or 

 principally the properties which have been called spiritual, we are 

 precluded an analysis of related disease, conducted with a view to 

 be informed of precise states and efficient causes. 



2. In those cases of related disease which happen between 

 seats which are connected by function, we are sometimes able to 

 say, as in the case of paralysis, happening from injury of the brain, 

 the secondary disease is here produced by privation of accustomed 

 properties, &c.; in a case of convulsions, we should perhaps be 

 inclined to say, in consequence of disturbance or injury of the 

 brain, properties are communicated to the muscles which produce 

 such and such phenomena; this, however, would be only an as- 

 sumption, though perhaps it might appear upon further inquiry 

 to be a probable one. But, in a general way, no advantage can 

 result from an attempt at investigating according to this division, 

 because, although it is the only one by which we can seek for 

 sensible evidence, it is not adapted to subjects where our best in- 

 formation must be inferential, and that too founded upon analogies 

 both numerous and obscure. 



3. Conditions of seats may be related either directly, as by 

 the properties of life occupying the seats, or indirectly, as by 

 relation of the properties of life of a seat with the preparation or 

 distribution of the fluid material, which again is related with other 

 seats. Sufficient has already been said by way of indicating that 

 complexity which must be unravelled by him who is ambitious of 

 giving a complete analysis of any one case which might be chosen 

 as a specific subject. Without here attempting any further an 

 analysis which belongs to particular inquiry, I shall consider 

 related disease after a looser fashion. 



