WASTE AND REPAIR. 221 



or group of organs, as the muscles, necessarily entails in- 

 creased activity in other organs, as in the heart, lungs, and 

 nervous system, it is clear that special waste and general 

 waste are too much entangled to admit of a definite relation 

 being established between special waste and special activity. 

 We may fairly say, however, that this relation is quite as 

 manifest as we can reasonably anticipate. 



§ 64. Deductive interpretation of the phenomena of Re- 

 pair, is by no means so easy. The tendency displayed by an 

 animal organism, as well as by each of its organs, to return to 

 a state of integrity by the assimilation of new matter, when it 

 has undergone the waste consequent on activity, is a tendency 

 which is not manifestly deducible from first principles; 

 though it appears to be in harmon}^ with them. If in the 

 blood there existed ready-formed units exactly like in kind 

 to those of which each organ consists, the sorting of these 

 units, ending in the union of each kind with already existing 

 groups of the same kind, would be merely a good example of 

 Segregation (First Principles^ § 163). It would be analogous 

 to the process by which, from a mixed solution of salts, there 

 are, after an interval, deposited separate masses of these 

 salts in the shape of different crystals. But as already said 

 (§54), though the selective assimilation by which the re- 

 pair of organs is effected, may result in part from an action 

 of this kind, the facts cannot be thus wholly accounted for; 

 since organs are in part made up of units which do not exist 

 as such in the circulating fluids. We must suppose that, as 

 suggested in § 54, groups of compound units have a certain 

 power of moulding adjacent fit materials into units of their 

 own form. Let us see whether there is not reason to think 

 such a power exists. 



" The poison of small-pox or of scarlatina," remarks Mr. 

 (now Sir James) Paget, " being once added to the blood, pres- 

 ently affects the composition of the whole : the disease pursues 

 its course, and, if recovery -ensue, the blood will seem to have 



