Note 890 — Chapter V · (continued 3)

‘Nature being pretty constant in the kind and number of the different parts peculiar to each species of animal, as also in the situation, formation, and construction of such parts, we call every thing that deviates from that uniformity a “monster,” whether (it occur in) crystallization, vegetation, or animalization. There must be some principle for those deviations from the regular course of nature, in the economy of such species as they occur in. In the present inquiry it is the animal creation I mean to consider. Yet, as there may be in some degree an analogy between all the three (kingdoms of nature), I shall consider the other two, so far as this analogy seems to take place.’ … ‘Monsters are not peculiar to animals: they are less so in them, perhaps, than in any species of matter. The vegetable (kingdom) abounds with monsters; and perhaps the uncommon formation of many crystals may be brought within the same species of production, and accounted for upon the same principle, viz. some influence interfering with the established law of regular formation. Monsters in crystals may arise from the same cause, as mentioned in the “Introduction;” viz. either a wrong arrangement of the parts of which the crystal is to be composed, or a defect in the formation, from the first setting out being wrong, and (the formation) going on in the same (wrong) line. The principle of crystallization is in the solution; yet it requires more to set it agoing, or into action, such, e.g., as a solid surface. The deficiency in the production of a true crystal may be in the solution itself; or, I can conceive, that a very slight circumstance might alter the form of a crystal, and even give the disposition for one (crystal) to form upon another. Quickness in the progress of crystallization produces irregularity and diminution in size.’ Hunter's Essays, London, 1861, vol. i. pp. 239–241. The reader must remember, that, when these remarks were written, the phenomena of crystallization had not been subjected to that exact mathematical treatment which subsequently revealed so many of their laws. Indeed, the goniometer was then so coarse an instrument, that it was impossible to measure the angles of crystals with accuracy.