a clubbed adunque state of the finger nails, and in Morbus Addisoni betwixt disorganized supra-renal capsules and pigmentary skin discolouration. Unable to rationalize, we class such phenomena as these under the wide head of "Correlations of Growth." The very vagueness of the phrase prevents us from even momentarily deluding ourselves with the idea that it amounts to an explanation, and to more therefore than an expression, of facts. It cannot be accused of striving to conceal the flimsiness of its thought by a magnificent display of archaic words, as certain exchequers would fain conceal their bankruptcy from the world by a copious issue of paper money. Herein lies its great merit.
On a future occasion I shall consider the nature of the Hybernating glands, if so they may be called, of certain hybernating and non-hybernating Insectivora and Chiroptera, and the possibility of classing them as growths tautogeneous with the highly developed mesenteric and cervical lymphatic glands found in many of those creatures.
And, before concluding, I would mention yet another class of structures, the existence of which admits of being rationalized upon yet another principle. These structures, fixed and settled in the adult organism, speak of a time when the sex was as yet unfixed and unsettled in the developing embryo, and accessory organs of either kind were, if so we may say, prepared so as to be in readiness to meet either event. The mammary glands, the Weberian organ, and the cysts of Morgagni of the adult male, the round ligament and the canals of Nuck and of Gärtner of the adult female economy, may have the history of their existence thus read.
As more and more vera causæ assert their existence and vindicate their rights, the ancient realm of Archetypal Ideas will suffer more and more serious curtailment.[1] But, like other foiling empires, it too will find its advocates to speak of it as being an "essentially conservative power;" though after short campaigns it has, once and again had to resign some of the fairest provinces in the world of thought, its existence will still be said to be necessary for the "preservation of the due balance of power" amongst rival biological principles.
Let us hope that in the interludes of Rhetoric the Logic of Facts may find a moment to make itself heard. It will teach men mundum quærere non in microcosmo suo sed in mundo majore, to hold of Nature that her ways are not as our ways, nor her thoughts as our thoughts. The notion of type may help man's weakness, but it by no means therefore follows that it regulates Nature's operations; it may enable us to colligate phenomena, but it may no more for that be the cause of their evolution than the mule's panniers which carry home the grapes are, by virtue of this their function, the cause of the growth of the vine.
- ↑ Even in Mr. Herbert Spencer's "First Principles," we find at page 22, the following sentence. "In Biology we are beginning to progress through a fusion of the Doctrine of Types with the doctrine of adaptations," and Mr. Darwin, in the last page but one to which we have referred in his writings, speaks of "Homology coming into play" as a really efficient physical agent.
