PAEALLEL CONDITIONS OF NUTRITION. 399 



lional activity is high and the nutrition defective, there re- 

 sults not growth but decay. If in an animal, any organ is 

 worked so hard that the channels which bring blood cannot 

 furnish enough for repair, the organ dwindles ; and if in the 

 body politic, some part has been stimulated into great pro- 

 ductivity, and cannot afterwards get paid for all its produce, 

 certain of its members become bankrupt, and it decreases 

 in size. 



One more parallelism to be here noted, is, that the dif- 

 ferent parts of the social organism, like the different parts 

 of an individual organism, compete for nutriment; and 

 severally obtain more or less of it according as they are 

 discharging more or less duty. If a man's brain be over- 

 excited, it will abstract blood from his viscera and stop 

 digestion ; or digestion actively going on, will so affect tne 

 circulation through the brain as to cause drowsiness ; or 

 great muscular exertion will determine such a quantity of 

 blood to the limbs, as to arrest digestion or cerebral action, 

 as the case may be. So, Ukewise, in a society, it frequent- 

 ly happens that great activity in some one direction, causes 

 partial arrests of activity elsewhere, by abstracting capital, 

 that is commodities : as instance the way in which the sud- 

 den development of our railway-system hampered commer- 

 cial operations ; or the way in which the raising of a large 

 military force temporarily stops the growth of leading in- 

 dustries. 



The last few paragraphs introduce the next division of 

 our subject. Almost unawares we have come upon the 

 analogy which exists between the blood of a living body, 

 and the circulating mass of commodities in the body politic. 

 We have now to trace out this analogy from its simplest to 

 its most complex manifestations. 



In the lowest animals there exists no blood properly so 

 called. Through the small aggregation of cells which make 



