spindle-celled, with or without pigment, round-celled, myxomatous, giant-celled, and the like. There are few of these mesoblastic tumours of the soft parts, or of bones as well, in which traces of the embryonic functions of the tissues may not be found by careful search and analysis.* But the functional memory is feeble, and the result is that the structural effects are either undecided, confused and grotesque, or if the type be uniform, as in many sarcomata of soft parts, it corresponds to nothing actually existent among embryological tissues. In many such cases the embryonic memory becomes a confirmed habit, and in not a few such cases the habit impresses itself upon other organs and parts in the form of secondary tumours due to infection.

The best illustration of the doctrine of embryonic memory as applied to tumours is a dermoid cyst of the ovary. This kind of tumour, as I have elsewhere written,† "shows to the fullest extent what the embryonic mesoblast can do in the way of fantastic new productions. Not only blood and bone, but teeth, skin, hair, glands, muscle, and nerve are produced as the tumour-constituents of these remarkable new growths. Their usual seat, and the invariable seat of the most perfect of them, is the ovary; and the ovarian is just that mesoblastic tissue upon which the

* See a paper by the author, "Illustrations of the Pathology of Sarcoma, from cases of Subcutaneous Cystic Tumours," Journ. of Anat. and Physiol.,' April, 1879.

"Pathology," 1. c., § 4.

memories of development are as if concentrated; for it is from an ovarian cell that the embryo grows in the perfect likeness of the parent. These selected cells of the ovary, or, in other words the ova, are specially charged with the recollections of the past history of evolution and growth; and the rest of the ovary appears to possess the same lively memory, if not to the same extent, yet to a much greater extent than mesoblastic tissue elsewhere. The stroma of the ovary is the best example in the body of embryonic spindle-celled mesoblast; only in some animals does it become normally fibrous, and in any animal it may revert to embryonic characters with the greatest ease at the generative periods or at other times, and even in extreme old age."

With these illustrations of mesoblastic cells and tissues retaining the memory of their embryonic and developmental phases, I shall now pass on to the more practical consideration of morbid habit.

CHAPTER IV.

HABIT AS A CAUSE OF LONG-STANDING CATARRHS.

THE Occurrence of the word "habit" in the title of this chapter offers a convenient opportunity for making some remarks on the use of that term in medical writings.

In medical writings down to quite recent times we frequently read of the habit, of the influence of medicines on the habit, of the way in which mercury passes out of the habit, of the habit acquiring a febrile tendency, and so on. Habit was in fact equivalent to constitution, crasis (or mixture of the humours), temperament, or even the body or organism in general. Habit in that peculiar sense, or rather its Greek equivalent, has come down to us from Aristotle; and its universal use in medical writings, where other words would have been less ambiguous, is an evidence of the domination of the Aristotelian philosophy. It was one of Aristotle's favourite idioms to employ under certain circumstances xuv (habere) with the adverb instead of εiva (esse) with the adjective (e.g. exuv κακῶς, instead of εἶναι κακός). Accordingly the word Es (habitus) became the corresponding abstract It never meant anything more than a condition

noun.

or state, and in old medical writings it is common to find the Latin equivalent habitus used interchangeably with status. "Eğiç survives for us in cachexia, which is simply Aristotelian for bad condition.

Such is the origin of the classical, mediæval, and even modern talk about the habit. In an essay on "Habit physiologically considered," by the late Dr. Symonds, of Bristol, reference is made to the traditional medical way of speaking of the constitution or individual state as the habit, the writer being evidently under the impression that the learned usage was not irreconcilable with the everyday meaning of the word. "Perhaps in all senses of the word," he says, "we shall find a connexion with its etymology, and that it has reference to something which has been held (habitus), retained after being acquired; something added to the individual, and henceforth always associated with him." No doubt the old phrase "habit of body" is now and again used in modern writings to express something acquired and retained, some habitual tendency, or the like. But that is not the meaning of the phrase in medical Latin, where habitus had no suggestion of consuetudo. It is well to understand clearly at the outset that it is habit in the everyday English sense of use and wont, and not in the Aristotelian sense of is, that is to be the subject of the following chapters. It is possible that constitution, temperament, crasis, dyscrasia, cachexia, and the like could be shown by an exercise of ingenuity to have a good deal to do with use and wont; but that

subject is altogether remote from my purpose. I come at once to the more obvious illustrations of morbid habit.

The memory of development which the common binding tissue and other tissues of mesoblastic descent never quite lose, is a faculty of reproduction that pertains to the individual cells. But everywhere in the body we have to reckon with the nervous system; and as the nervous system is in an especial way associated with memory, in all the commoner acceptations of the term, it will be desirable to consider shortly at this stage how far the co-operation of a piece of nervous mechanism is necessarily implied in the existence of unconscious memory.

A remark of Hering's on the nervous connexions of the ovary will bring this question to an issue. Having pointed out that all parts of the body are in intercommunication by means of innumerable nerve-twigs and the central organs, he proceeds to say (l. c., p. 15): "We see also that the developmental process in every germ that is destined to be an independent creature reacts powerfully on the conscious and unconscious life of the whole organism. Does not this show to us that the organ of germ-formation stands in closer and more important relation to the rest of the body, and to the nervous system in particular, than other organs, and conversely, therefore, that the conscious and un-conscious events of the organism at large find in the ovary a louder echo than elsewhere? Herein we have a plain enough indication of the direction in which lies