84 Mr. Burnett on the Development 



the case with the stomach and the heart ; then by a licence 

 still more exceptionable, analogy and affinity were confounded 

 with eacli other, and all deference both to structure and to 

 function disregarded ; for in this instance heat was regarded 

 as the heart, and the earth as the stomach of plants. Simi- 

 larity of function is often found, however, to be a far less 

 erring guide than similitude of external form and structure ; 

 the one is more general and less modified than the other, for 

 very diversified means may be adopted to achieve the self- 

 same end : thus nutrition may be performed without a mouth 

 to receive, teeth to chew, or even a stomach to digest the food ; 

 respiration may take place without either lungs or gills ; pre- 

 hension without either hands or claws ; and progression with- 

 out wings or feet. 



Thus among plants, although the root may in general 

 be the prime organ of nutrition and the seed of reproduc- 

 tion, many plants are efficiently nourished and propagated 

 without either root or seed ; at least without those modifications 

 of the nutritive and reproductive systems being present, which 

 are ordinarily so called; the functions remaining when the 

 organs have disappeared, i. e., the ends being still the same, 

 though the means have been greatly varied. From these cir- 

 cumstances such plants have been called imperfect plants; 

 yet this has been only done, because they have been imper- 

 fectly considered ; and still more, because the abstract idea 

 formed by many phytologists of a seed or of a root, has been 

 rather the amplification of the idea of some particular seed or 

 root, e. </., of an acorn or an oak root, than an enlarged and 

 liberal view of the various modifications of external configura- 

 tion under which the nutritive and reproductive functions 

 may be efficiently performed; and consequently without refer- 

 ence to the numerous forms under which these systems are 

 developed : i. e., under which the potential root and seed can, 

 nay do, very frequently appear. Hence from these imperfect 

 premises has arisen the deduction of characters as essential, 

 which in truth are only accidental to each prime organism ; for 

 not only have the most highly developed organs of men, ani- 

 mals, and plants been comparatively referred to, to explicate 

 the obscurities incident to each, but the organs of the one 

 have too often been selected as rules or examples for the other ; 



