Wednesday, 21 March 2012

The Birth of Modern Teratology

What follows is an excerpt from a British Review Article on M. Isidore Geoffroy St. Hilaire's General and particular History of Anomalies of Organization in Man and Animals which appeared in The British And Foreign Medical Review (Vol 8, No. 15) July, 1839.

Histoire générale et particulière des Anomalies de l'Organisation chez l'Homme et les Animaux, outrage comprenant des Recherches sur les Caractères, la Classification, etc. des Monstruosités. Par M. Isidore Geoffroy Saint Hilaire, M.D., &c. &c.—Paris, 1832-36. Trois Tomes, avec Atlas. 8vo, pp. 746, 571, 618.

A general and particular History of Anomalies of Organization in Man and Animals, comprising Researches into the Characters, Classification, &c. of Monstrosities. By M. Isidore Geoffroy St. Hilaire, M.dD, &c. &c—Paris, 1832-36. 3 Vols. 8vo, with an Atlas.

Although some years have elapsed since the greater portion of the work before us was published, yet, as no sufficient account of it has hitherto appeared in our language, we think it important that our readers should no longer be deprived of the highly interesting and valuable information it contains, and shall therefore now present them with an analysis of it. In executing our task we shall confine ourselves almost exclusively to the exposition of the author's views; introducing our own opinions but sparingly, even when they are at variance with those maintained in the original treatise. On some future occasion we may take up the whole subject fundamentally; our present object being rather to supply facts than to criticise doctrines.

The object of M. St. Hilaire's work is to give a complete history of the subject of monstrosities: under which name all the various congenital irregularities of form and structure, occasionally met with in man and animals, are generally included. The author has collected together a great number of facts, relating to the different forms and degrees of anomaly, which he has systematically arranged in classes, orders, &c.; and he has afterwards endeavoured to establish the laws and general relations to which all the individual facts may be referred. He has shown how these laws and these relations are themselves only derived from the common laws of organization, and how, among the numerous theories of the formation and growth of animals which have been proposed in modern times, those which are not applicable to anomalous cases are also inapplicable to normal facts in general, and ought to be rejected; and many principles, on the contrary, but slightly established at present by the study of natural facts, find in the phenomena of monstrosities complete elucidation. M. Isidore St. Hilaire has also pointed out that this subject embraces all the conditions of organization in the various classes of organized beings, and that there is scarcely any general fact, auy anatomical or physiological law, on which it does not throw light and either confirm or disprove. Thus the necessary consequence of an exact and profound knowledge of anomalies will be, that the study of normal and abnormal facts, intimately associated together, will lend to each other a mutual and powerful support.

A vast collection of most valuable materials on this subject may be found scattered through various publications on natural and medical science; but before the younger St. Hilaire (who has largely profited by his father's labours) undertook the task of collecting them, there existed no modern work which professed to give a complete and separate account of the various anomalies of organization, such as might serve as a textbook, and for the purposes of reference, in which all the varieties of monstrosity which have been met with should be recorded, as well as the opinions of different writers on their nature and causes.

Our author thinks that the consideration of the various kinds of monstrosity, with the laws and causes of their formation, should form a distinct branch of science, and should be treated of separately from pathological or general anatomy and physiology, embryology, or zoology; with all of which they have a very close connexion, and together with some of which they have mostly been described. To this particular subject which M. Isidore St. Hilaire has thus isolated from the sciences by which it is surrounded, he has proposed that the name of Teratology* should be given, which he considers preferable to the old denomination of monstrosities, the term which was previously given to all kinds of congenital malformation. Our author's views as to the separate place which Teratology should hold in science are supported by Meckel, who supposes that the various species of monstrous formation compose a series rising by regular gradations, from the natural shape to the most unnatural deformity: and that the intermediate steps are not constituted by single or individual cases, but that every variety of monstrous formation is accurately repeated in other individuals; so that, in fact, a separate and independent kingdom of monsters might be established.

Monstrosities have attracted the attention of philosophers as well as the vulgar in all ages. Among the ancients, Hippocrates, Aristotle, Pliny, Galen, and even Empedocles and Democritus noticed their occurrence and investigated their causes; and these early writers had almost as accurate notions of the nature, and gave as faithful descriptions of monstrous formations, as any of the authors on this subject before the commencement of the eighteenth century. Indeed, the history of monsters, till very lately, was composed of a collection of marvellous tales, inaccurate descriptions, and absurd and superstitious prejudices. This long period of ignorance, with respect to their true nature, may be called the fabulous period in the history of the science, and cannot be said to have terminated before the time of Ambrose Paré. A few authentic and interesting cases, it is true, had been already recorded; but these were only rare exceptions, which attracted little attention, except when some author tried to give a new and ridiculous explanation of them, derived from the fanciful ideas which were then exclusively prevalent. In fact, monsters were regarded by the writers of the seventeenth century as by those of preceding ages, as prodigies and sports of nature, arising from supernatural or unnatural causes.

After the fabulous, succeeded what St. Hilaire has called the positive period in the history of anomalies; it comprises about the first half of the eighteenth century. Evident progress now commenced, and facts were correctly observed, though still often explained on false principles. The most celebrated authors of this age on teratology were found among the members of the French Academy. Méry, Duverney, Winslow, Lémery, and Littre may be particularly mentioned. In the works of these great men, we not only find numerous facts accurately observed and described, but many judicious remarks and violent attacks against ancient prejudices. In place of those explanations of the phenomena of monstrosity, which were admitted by the superstition of the preceding period, they endeavoured to substitute scientific and reasonable theories. The causes of monstrosity particularly excited attention; and though many errors were fallen into, for want of the support of a sufficient number of facts, yet it was discovered that one of the greatest difficulties was involved in the question, whether monsters were formed so originally, or whether the monstrosity was accidentally acquired. A very long and able controversy was carried on concerning this point between Lémery and Winslow, the former of whom contended that monstrosities were formed or arose during the growth of the embryo; and modern discoveries in embryology have shown that he was correct, though his rival, who held that the germs were originally monstrous, was considered to have triumphed at the time.

The labours of these celebrated academicians conducted the science to its last epoch, which may be denominated the scientific, and which extends from the middle of the eighteenth century to the present time. It may be divided into many periods; and it will be seen that a vast difference exists between the state of teratology at its commencement and end, owing to the rapid progress which science has made. Haller may be said to have commenced this era, though Morgagni had previously corrected several erroneous opinions respecting the nature and causes of monstrous formations. Haller, in his treatise De monstris, collected all the facts relating to this subject which were recorded by his contemporaries and predecessors, submitted them to a judicious analysis, and deduced from them several conclusions eminently calculated to promote the advancement of this study. Haller, however, fell into some fundamental errors, the most important of which was that respecting the mode of the development of the embryo. He supposed (and his theory prevailed till very lately, and is now partly entertained by some physiologists,) that the development of the organs of the foetus was centrifugal, or that the heart, brain, spinal cord, &c. were formed before the vessels and nerves which were gradually developed from them. This theory, as we shall presently show, is contrary to those laws of formation by which the greater number of anomalies are explained by our author and other teratologists.

The rapid advances which have led to the present state of this department of science are owing to the indefatigable researches of modern anatomists. The study of general and comparative anatomy led the way to the true method of investigation, viz. that of comparing adult man to the embryo, and various animals to man, both in the adult and foetal states. This comparison has given rise to two new methods of investigation, which are now almost universally recognized in the science of anatomy. One discloses the true laws of organic formations; the other embraces the general facts of the structure of animal bodies, considered in all ages and all species. Both of these methods reveal to us important knowledge concerning the composition of organs: the one plan assists us in learning the mode of their formation; and the other decomposes them by a learned analysis, and shows us the elements, everywhere identical, disposed according to invariable rules. Embryology is thus placed upon its true basis, and philosophical anatomy created. Among those naturalists to whom we are indebted for these researches, we may particularly enumerate Geoffroy St. Hilaire (the father of our author) and M. Serres in France, and Frederic Meckel and Tiedemann in Germany.

The various species of monstrous formations have been referred to three classes, viz.

1. Anomalies which arise from arrest of formation or development, in which various parts are found either imperfectly formed or altogether deficient.

2. Anomalies from excess of formation or development, in which some organs exceed their natural limits either in size or number.

3. Anomalies which result neither from arrest nor excess of formation and development, but in which the formative process seems to have been simply perverted, thus producing various modifications in the direction and situation of organs. In this class M. Isidore St. Hilaire includes the entire group of compound monstrosities, which result from the junction or fusion of two or more separate individuals. These have generally been referred to one of the previous classes.

The explanation of these different varieties of organization, or the laws of anomalies, must be derived from the general laws or principles of organization, which the study of philosophical anatomy and embryology have revealed; and, before proceeding to the consideration of the different varieties of monsters, we shall briefly mention the most interesting of these laws, and explain the manner in which they elucidate the different classes of monstrosities.

1. The first and most important is the law of unity of organic composition.

One great principle reigns over the whole of zoological science, that there is a unity of plan in the animal kingdom. Philosophical anatomy has shown us that the organs of animals are composed of materials which are always essentially the same, and which are combined according to definite rules; and that curious and unexpected analogies often exist between beings placed at the opposite extremities of the scale. If we admit the existence of a distinct and peculiar plan of organization for each species, or even in different families, we only obtain partial views, and the science will be reduced to the sterile observation of facts, without reciprocal connexion, rational analogies, or possible consequences. If, on the contrary, we elevate our ideas to the conception of a unity of plan pervading the whole animal kingdom, we shall only see in the multitude of beings which compose the animal series, the innumerable parts of one immense whole, the infinite varieties of one and the same type.

If we apply to the solution of the difficulties which this subject presents, the theory of inequalities of formation and development, we shall find it equally applicable to zoology as to teratology; and the fundamental truth will be apparent, that one or more metamorphoses, to a greater or less extent, sometimes consisting merely in a simple change in the mode of evolution of an organ, will explain all those varieties of form and structure which at the first aspect seem to arise from essential differences in the formative process.

The series of species in the animal kingdom seems to be parallel with the series or stages of formation or development in any individual being, or, in fact, with the series of ages in that being; and the facts of one are reciprocally connected with and explain those of the other. The connexion between teratology and zoology is now seen. The theory of inequality of formation and development relates both to the series of ages in the embryo and the series of zoological species, as well as to the series of monstrosities: it shows the parallel relation between the first and second as well as between the first and third; and by the same laws the series of zoological species and monstrous cases are necessarily analogous and parallel to each other. Thus, in an abstract point of view, all the differences between beings either normal or abnormal may be embraced in the same considerations and referred to the same formulae: as, for instance,—the inferior beings are, as it were, the permanent embryos of animals higher in the scale; and, reciprocally, the superior beings, before they arrived at the definite forms which characterize them, have transitorily offered those of the lower animals. This must not be taken, however, quite literally; for the resemblance or analogy is only seen between individual organs, not entire beings.

By this law of unity of type in the formation of animals (which has been so fully exposed in the works of the elder St. Hilaire, Meckel, and Serres,) may be explained the resemblances which have so often been observed between the anomalous states of one species and the natural form of another. Every animal in whom there has been arrest of development should realize in some of its organs the conditions met with among the inferior classes. Excess of development, on the contrary, should cause a resemblance between the animal which is the subject of it and some of the beings higher in the scale. Many examples of monstrosity have been brought forward in support of this theory, and we may briefly state a few of them. The most numerous cases are those in which the higher animals by arrest of development present the characters which are natural to some inferior species. Thus man, when affected with monstrosity, often has a marked resemblance in some characters with different mammalia, as by the persistence of the tail,[i] and by many anomalies in form either of the limbs, body, or head. Thus, by the existence of a cloaca, labial fissure, duplicity of the uterus, smallness of the brain, and absence or imperfect state of the convolutions, the malformed human foetus presents characters which are all found existing naturally in various species of rodentia, as the beaver, &c.

In some monsters there has been found bifurcation of the glans penis or clitoris, and two vaginae, a disposition of parts existing normally among marsupial animals. By imperforation of the vulva, and a separate termination by distinct orifices, of the sexual and urinary organs, with imperfect development of the eyes, the genus called aspalasomus and other monsters realize in man those organic conditions, which in the normal state distinguish the mole and some other insectivora from all other mammalia. In the genus of monsters, phocomeles, the limbs are shortened, the hands and feet appearing to exist alone, and to be inserted immediately on the trunk, as in the seals and the herbivorous cetacea. In the rare monster, ectromeles, the limbs are nearly or altogether deficient, as in the ordinary cetacea.[ii]

We may also often observe some of the conditions of animals still lower in the scale, realized in human monsters; thus, there may be a rudimentary state of the palatine arch, as in fishes; imperfect development of the diaphragm, as in all oviparous animals; a communication between the different cavities of the heart, as in reptiles; an absence of the brain and spinal marrow; and a nervous system composed only of ganglions and nervous filaments, as in the articulated animals.[iii]

Although the cases are much more rare in which the inferior animals resemble the higher, from excess of development,[iv] yet many instances of this kind have been met with. St. Hilaire has seen several individuals among the carnivora in which the tail has disappeared, and the spinal marrow has ascended in the vertebral canal, as it does in man and the most highly-organized quadrumana. This anomaly also realizes the conditions met with in some animals much lower in the series, as the anourous batrachians or frogs, where there is a continuance or excess of the process of development in the change from the tadpole to the perfect animal.

The possibility of referring the various species of monsters to a common type is a necessary and easy deduction,—in fact, an indispensable conclusion to be drawn from the theory of the unity of organic composition. When we admit that the entire classes of the animal kingdom are established upon one and the same plan, it becomes absurd to allow the existence of many types in one family. From the natural relation which exists also between the different degrees of monstrosity and the links in the animal chain results a complete demonstration that monstrosity is not a blind disorder springing from freaks of nature, but a particular class governed by constant and precise rules, and capable of being systematically divided into definite tribes and genera. The elder St. Hilaire, however, is disposed to consider each individual monster as constituting in itself a distinct species; and he does not agree with Meckel, that every variety of monstrous formation is accurately repeated in other individuals.

2. The second law which we shall mention as being closely connected with teratology is one of the fundamental principles of embryology: the basis, in fact, upon which that science rests, viz., that no organs originally preexist in the ovum, but are all formed at various periods of its growth. Necessarily very minute and simple at the time of their early origin, the different organs afterwards pass through a series of changes in the process of development. These changes are far from being equal either in number or importance, whether we compare together the same organ in different beings, or different organs in the same being; so that, when arrived at their definitive or permanent state, some have passed through a greater number of phases, and have departed much more from their primitive conditions than others. Such is the normal but not the invariable mode of development: an organ may stop beneath its ordinary degree of perfection, or even be entirely abortive; it may, on the contrary, exceed the natural term of its evolution, and thus will arise the two groups of anomalies, opposite in their conditions of existence, and also in their causes, to which so many of the species of monsters have been referred, viz. arrest and excess of development.

The admission of the law of non-preexistence of organs in the germ is fatal to the doctrine of original monstrosity existing before fecundation: a doctrine conceived by Licetus and the older writers on this subject, but which owed its celebrity to its adoption by Winslow and Haller. It would now have been almost forgotten had not Meckel lately attempted to revive it for the purpose of explaining the occurrence of certain monstrosities, the origin of which cannot be understood in the present state of teratology, such as the retroversion of the abdominal limbs and some other peculiarities of organization, which are constantly associated with the junction of the legs in the monsters named symeles. M. St. Hilaire says that the only argument brought forward by Meckel in support of his hypothesis is the impossibility of finding a satisfactory explanation of these anomalies by the theory of accidental production of monstrosities: this is true in the present state of science; but there is no reason why the obscurity of this case should not one day be cleared up, like many other facts in teratology, which were formerly thought inexplicable, and cited as certain proofs of the original production of monstrosities, but which the ulterior progress of science has discovered to be in support of the inverse theory.

According to the law which admits the formation and not the evolution of organs, monsters from arrest of development may be considered in some respects as permanent embryos: they show us at the termination of intra-uterine life some of their organs in the simple state in which they were first formed; as if nature had stopped in her course for the purpose of allowing us the opportunity of observing her processes.

3. A third law is that of eccentric development. We have already remarked that Haller (and he was followed by all the anatomists of the eighteenth century) considered that the heart was formed before any other organ, and was itself the origin of all the others; that it furnished the principal vascular trunks, which afterwards subdivided into branches more and more minute. In the same manner the nervous trunks were considered to derive their origin from the cerebro-spinal axis, which was said to be first developed, and the larger nerves were afterwards thought to ramify into the minute branches; in other words, all the vessels and nerves, subdividing more and more, proceeded from the central parts of the nervous and vascular systems towards the organs placed on the surface of the body, to which they gave nourishment and life. This theory is denominated that of centrifugal development, and has still many supporters.

The inverse doctrine, that of eccentric or centripetal development, was proposed by M. Serres, and is warmly supported by Geofiroy St. Hilaire and his son: all the laws of teratology proposed by the father and followed by his son in the present work are founded upon it, and by this theory a great number of anomalies are explained. These anatomists say that the vessels and nerves are formed before the heart and nervous centres; they first originate in the superficial organs on the surface of the body, and are gradually developed towards the centre; in support of this opinion it is said that the heart, brain, and spinal cord have all of them been found wanting in different monsters, while the vessels and nerves have never been seen wholly deficient. The large trunks are also found more frequently irregular in their course and distribution than the superficial branches of an artery or nerve, and the contrary should be the case if the development was centrifugal, as it has been observed that those organs which are latest formed are the least constant.

According to the observations of M. Serres, the development of the body commences on the surface of the two lateral halves, each central and single organ being originally double, its right and left portions are at first distinct and separate, and become afterwards united. If by any causes, as arrest of development, the union of these two half-organs is prevented from taking place, if this primitive state of formation becomes permanent, two lateral organs are formed, which may be either entirely distinct or only partially separated, according to the period of formation at which the arrest of development took place. The median labial fissure (often confounded with the lateral fissure or true hare-lip) has been thus explained, as well as fissure of the palate, scrotum, urethra, and spinal fissure or spina bifida, &c. M. Serres also states that the hollow organs situated in the median line are composed originally of two halves; as well as the solid organs; and his observations have been, to a certain extent, confirmed by Dr. Allen Thomson, and others. Thus, according to our author, there are at one period two hearts (this organ is placed in the first instance in the median line), two aortae, two vaginae, uteri, bladders, &c. These organs are considered to pass through three successive stages in the process of development: in the first they are completely double, and the two portions quite separate; in the next stage they approach and unite in the median line, the two inner walls being applied against each other, and at the third period they become definitely fused, the inner walls being removed, and all traces of separation lost. If by arrest of development the second stage of formation becomes permanent, the inner walls of the primitive organs which unite together and form naturally a temporary septum are not removed, and the organ is intersected by a longitudinal partition. Such an anomaly is sometimes met with in the human subject, affecting the vagina and uterus, and realizing the natural conditions of the sexual organs in some marsupial animals.

Another fact which is dependent upon the law of centripetal development is the greater constancy of form in those organs which are of early formation than in those later developed. When any cause comes into action at any period of uterine life, by which the process of growth may be disturbed, those organs which are already nearly or fully evolved will necessarily be little or not at all altered; but a very marked change, on the contrary, may be effected in those parts which are very imperfectly developed, or whose formation has not even commenced. In the latter case complete atrophy may be effected.

If we add, that in most of the systems of organs the different parts are subordinate in their formation one to another, the second being produced by the first, the third by the second, and so on, we shall see that the suppression of any one of them, without having any influence on those which preceded it, will necessarily cause the complete absence of all those which ought to have followed it in the order of development. The results of observation perfectly confirm these remarks; it has been found that the umbilicus and small intestines are the parts most constant in monsters, and also the organs first formed in the embryo; the spinal cord also is less often wanting than the brain which it precedes, the aorta than the heart, &c. The superficial and lateral parts of the body are also much more constant than the central or medial organs, they often exist when the latter are wanting, and they frequently present a regular conformation when the latter are seriously modified or very incomplete. Many cases may be met with where the different parts or organs have been reduced to their external covering or integument; thus in the monsters named cyclocephali and otocephali, in which the two eyes or ears are in contact, or united in one, the nose is entirely rudimentary, the bones, &c. being deficient, and only the skin remaining, which is sometimes prolonged in the form of a snout or trunk: sometimes one of the abdominal limbs has been found in this rudimentary state, and in some very imperfect monsters the whole being seems to be reduced to the tegumentary covering, inclosing a few unconnected parts, as bones, vessels, &c.

[i] In the early stages of formation of the human fetus, there naturally exists a prolongation of the coccyx, which is removed by the progress of development.
[ii] It is proper to observe, however, that some of these cases were probably instances of  ‘spontaneous amputation,’ and cannot, therefore, be properly called monsters at all. Rev.
[iii] In the last of these cases, no real analogy can bo said to exist.—Rev.
[iv] These anomalies appear to be more rare, perhaps, than they really are, on account of the much greater number of monstrosities that arc observed and examined in man than among animals.

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