GROWTH. 109 



kind must not be confounded with that growth, properly so 

 called, of which we have here to treat. 



The next general fact to be noted respecting organic 

 growth, is, that it has limits. Here there appears to be a 

 distinction between organic and inorganic growth ; but this 

 distinction is by no means definite. Though that aggrega- 

 tion of inanimate matter which simple attraction produces, 

 may go on without end ; yet there appears to be an end to 

 that more definite kind of aggregation which results from 

 polar attraction. Different elements and compounds, habitu- 

 ally form crystals more or less unlike in their sizes ; and each 

 seems to have a size that is not usually exceeded without a 

 tendency arising to form new crystals rather than to increase 

 the old. On looking at the organic kingdom as a 



whole, we see that the limits, between which growth ranges, 

 are very wide apart. 3Lt the one extreme, we have monads 

 so minute as to be rendered but imperfectly visible by micro- 

 scopes of the highest power ; and at the other extreme, we 

 have trees of 300 feet high, and animals of 100 feet long. 

 It is true that though in one sense this contrast may be 

 legitimately drawn, yet in another sense it may not ; since 

 these largest organisms are made by the combination of units 

 that are individually like the smallest. A single plant of the 

 genus Protococcus, is of the same structure as one of the 

 many cells united together to form the thallus of some 

 higher Alga, or the leaf of a phcenogam. Each separate 

 shoot of a phsenogam is usually the bearer of many 

 leaves. And a tree is an assemblage of numerous united 

 shoots. One of these great teleophytes is thus an ag- 

 gregate of aggregates of aggregates of units, which sever- 

 ally resemble protophytes in their sizes and structures ; 

 and a like building up is traceable throughout a consider- 

 able part of the animal kingdom. Even, however, when 

 we bear in mind this qualification, and make our com- 

 parisons between organisms of the same degree of compo- 



