Having now treated of organized new growths in general, of their blastemata, and of the several processes through which these are engendered, we come to the special consideration of new growths.

What order ought we to observe in this discussion?

(1.) An arrangement based upon morphological relations is inadmissible:

(a.) The elements being in themselves far too uniform, in their secondary arrangement too multiform, and generally too little distinctive of the nature of the new growth.

(b.) The elements being mutable, what is one day in the embryonic state, is found further advanced on the morrow; whilst various grades of development are found to co-exist in juxtaposition.

(2.) Similar objections obtain against a division of new growths according to their main organico-chemical constituents; these being not alone convertible substances, but also liable to enter into various combinations in the same growth.

(3.) With respect to the distinction of new growths into homoeoplasiae and heteroplasiae, we have already once expressed an opinion. A systematic arrangement upon such a basis, irrespectively of its preternatural rigor, is open to the objection, that it breaks up new growths into two great series, in the first of which no doubt many points offer in the analogies for further subdivision. In the second, however, we are either driven to a ground of distinction alien to the system, er else compelled, in opposition to the principle itself, still to have recourse to comparison with normal textures.

(4.) How little the benign or malignant nature of new growths in general, affords a basis for a genuine classification is self-evident.

In order to avoid the difficulties alluded to, we shall here endeavor to observe a middle path, and treat of new growths in a series beginning with those which bear the evident tokens of benignancy, and whose ulterior development is for the most part one of progress into fibre; passing next to those differently constituted in these particulars.