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excessive irritability. We will suppose it to be ascertained that the 

 property denominated sensible organic contractility, or that which is 

 more immediately connected with the circulation, is alone interested 

 in this disease; the disease is said to Consist in an excess of irrita- 

 bility. Thus far we have stated a case which we must next examine. 



14. The word " excess" is applicable only to the sum or 

 quantity of that which is excessive. How, I would ask, is it ascer- 

 tained that the natural irritability is increased in quantity? I may 

 take it for granted, without presuming too much, that \ve have no 

 measure of the quantity of the principle of irritability. If it be 

 said that the effects of irritability furnish this criterion and this 

 proof; then I reply that it is in order to shew them to be the effects, 

 that the criterion and the proofs are wanting. If then we are unable 

 to estimate the quantity of irritability, why introduce it into our 

 reasonings] Why presume to explain phenomena by that which 

 itself stands equally in need of explanation? It may further be 

 urged, there is in the case supposed an excess of intensity or of de- 

 gree, rather than in the quantity of the principle resident in the 

 fteat of the disease. This may be compatibly with the application 

 allowed above to the word excess; of this " degree" we shall have 

 occasion to say a few words hereafter. 



15. But, to go further, let us allow that irritabilitv either in 

 quantity or degree can be measured in some way or other, loosely 

 or accurately, no matter which; let us allow this, and then examine 

 whether all those phenomena of the irritable ulcer are referable 

 to the quantity or the degree of the sensible organic contractile 

 power. 



1st, The discharge may be sanious and offensive : in what man- 

 ner does the degree of irritability regulate this particular? The only 

 function which is attributed to this contractility is to govern the 

 action of vessels: what rate of pulsation then, or if this objected to, 

 what modification of caliber is required to produce a sanious dis- 

 charge? Such a question, involving so much improbability, was 

 perhaps never thought of, it is therefore no wonder that it is not 

 answered. But that the secretion is not produced by any rate of action, 

 by any degree of the principle alone, seems to be proved by the fact 

 that an ordinary specimen of phlegmonous inflammation in some or 

 other of its periods embraces every rate of action, every condition 

 of an inflammatory diathesis; at least, if we cannot discriminate a 

 difference in favour of that connected with our sanious discharge, 

 we have no right to presume it. But suppose even that a difference 

 of action in the vessels were perceptible, suppose also that a suitable 

 caliber of the vessels were assumed (which last is supposing a pro- 

 perty superadded to that which merely governs the rate of pulsa- 

 tion), suppose all this and every other convenience, the effect would 

 then be that the fluids contained in the vessels would be circulated 

 or poured out either faster or slower than in an ulcer of a different 

 description. Now we know that simple pulsating tubes of a certain 

 area, a mere hydraulic process, can never give a product of secretion; 



