MEDICAL WORLD. VOLUME I. OCTOBER 29, 1856. NUMBER 5. HEREDITARY INFLUENCE, ANIMAL cur to him, perfectly heedless of the mass of AND HUMAN. 1. Traité de l'Hérédité Naturelle dans les Etats de Santé et de Maladie du Systéme Nerveux. Par le Dr. Prosper Lucas. 2 vols. 8vo. Paris. 1847-1850. 2. On the Physiology of Breeding. Two Lectures delivered to the Newcastle Farmers' Club. By Reginald Orton, M.R.C.S. Sunderland. 1855. 3. De la Génération. Par M. C. Girou de Buzareingues. Paris. 1828. cases in which the mothers have not been remarkable. The various theories imply variety of interest in the question, and a practical need for the solution. A subject at once so interesting and important may well claim some attention from us here; and we shall endeavor to disenThe problem of hereditary transmission, phy-gage it from all technical difficulties, so as to sical and moral, although one of the most in- present it in a form intelligible to the general teresting of physiological problems, is also one reader, and to clear up many misconceptions, of the most baffling. In spite of its obscurity, popular and scientific, which at present obit fascinates the inquirer; perhaps with all the struct the question. The three works placed greater force because of its obscurity, for, as at the head of this paper, with many others Spinoza truly says, men cease to admire that less directly bearing on the subject, will supwhich they fancy they understand; tum enim ply us with abundant facts, and may be revulgus rem aliquam se satis intelligere existi- commended to readers desirous of pursuing the mat quum ipsam non admiratur. The ques- inquiry. Dr. Lucas has in two bulky octavos tion of hereditary influence has descended gathered from far and wide a mass of material, from antiquity encumbered with prejudices and good, bad, and indifferent, with laudable dilideceptive facts, which seemed coercive and gence, but with a want of discrimination not so conclusive, but were in truth, only one-sided; laudable. He is erudite, but he has les déand encumbered still more with hypotheses fauts de sa qualité. His erudition is utterly formed in ignorance of Nature's processes. It uncritical; and yet it is obvious that the sole has reached us a problem still; every scien- value of the cases collected depends on their tific mind not prepossessed by an hypothesis, authenticity. It is the common error of erunor content to disregard a mass of facts, must dite men to imagine that quantity supplies the pronounce the answers hitherto proposed, defi- place of quality. They fancy themselves rich cient in the primary requisite of comprehend- when their purses are filled with forged notes; ing all the phenomena. Nevertheless, an- and, so long as these notes are kept from preswers abound. Every cattle-breeder, who sentation at the Bank, their delusion is unrises to the height of a theory, has his theory troubled. Dr. Lucas has far too many of on this complex matter, and acts upon it in the these notes in his purse: the reader must take breeding of cattle and poultry. Every village up his volumes with great caution. Mr. Orton gossip, every Mrs. Gamp, has her facts and her makes no such erudite display; but he has col opinions, which, in expansive moments, she de- lected some curious facts, both from his own livers with great confidence. Every physician experience and from the experience of other has his theory, especially with reference to the breeders. M. Girou is one of the authorities transmission of disease. Even the man of let- most frequently referred to by writers on ters is not without his generalization on the this topic. To vast practical experience in transmission of genius: all men of genius," cattle-breeding he adds very considerable phyhe tells you," have had remarkable mothers;" siological knowledge and force of intellect.. in support of which generalization he counts Heritage (l'hérédité), or the transmission of off upon his fingers the illustrations which oc-physical and mental qualities from parents to offspring, is one of those general facts of Na- from the first person they meet. From Cain ture which lie patent to universal observation. and Abel down to the brothers Bonaparte, the Children resemble their parents. Were this striking opposition of characters in families has law not constant, there could be no constancy been a theme for rhetoric. Nor is this all. of species the horse might engender an ele- In cases where the consanguinity may be said. phant, the squirrel might be the progeny of a to be so much nearer than that of ordinalioness, the tadpole of a tapir. The law, how- ry brotherhood, namely, in twins, we see the ever, is constant. During thousands of years same diversity; and this diversity is exhibited the offspring has continued to exhibit the in those rare cases where the twins have only structure, the instincts, and all the character-one body between them. The clebrated twins, istics of the parents. Every day some one exclaims as if the fact surprised him-"That boy is the very image of his father!" yet no one exclaims, "How like that pug dog is to its parent!" Boys or pug dogs, all children, resemble their parents. We do not allude to the fact out of any abstract predilection for tru isms, but simply to marshal into due prominence an important truth, on which the whole discussion of heritage must rest. The truth is this: Constancy in the transmission of structure and character from parent to offspring, is a law of Nature. - Rita and Christina were so fused together, that they had only two legs between them; two legs and four arms and two heads; yet they were quite different in disposition. The same difference was manifested in the celebrated Presburg twins, and in the African twins recently exhibited in London. It is clear then that offspring do not always closely resemble parents; and it is further clear, from the diversities in families, that they do not resemble them in equal degrees. Two brothers may be very unlike each other, and yet both like their parents; but the resemblance to the parents must, in this case, be variable. So that when we lay down the rule of constancy in transmission, we must put a rider on it, to the effect that this Constancy is not absolute, but is accompanied by a law of Variation. It is the intervention of this law which makes hereditary influence a problem; without it, heritage would be as absolute as the union of acids with bases. That this truth is not a truism we shall show by at once contradicting, or at least qualifying it. The very same experience which guarantees the constancy, also teaches, and with almost equal emphasis, that this constancy is not absolute. Variations occur. Children sometimes do not resemble their parents; which accounts for the exclamation of surprise when they do resemble them. Nay, the children are sometimes not only unlike their parents, they Some philosophers have tried to explain the are, in important characteristics, unlike their law of constancy in transmission, and its indeSpecies. We then call them Deformities or pendence of the law of variations, by mainMonsters, because, while their Species is dis- taining that it is the Species only, not the Intinguished by having four legs, they themselves dividual which is reproduced. Thus a sheep have six or none; while their Species possesses is always and everwhere a sheep, a man a man, a complex brain, they are brainless, or have reproducing the specific type, but not necessa imperfect brains; while their Species is known rily reproducing any individual peculiarities. by its cloven hoofs, they have solid hoofs, and All sheep resemble each other, and all men Dissemblances as great are observable resemble each other, because they all belong in moral characteristics. We see animals of to specific types. What does the reader say to ordinary aptitudes engender offspring some- this hypothesis? Burdach, who adopts it,† adtimes remarkable for their fine qualities, and duces his facts: for example, a dog from whom sometimes for their imbecility. The savage the spleen was extirpated reproduced dogs wolf brings forth occasionally a docile, amiable with perfect spleens; an otter, deprived of its cub; the man of genius owns a blockhead for fore paws, produced six young with their legs his son. In the same family we observe strik- quite perfect; in a word, "l'idée de l'espèce ing differences in stature, aspect, and disposi- se reproduit dans le fruit et lui donne des ortion. Brothers brought up together in the ganes qui manquaient au père ou à la mère." same nursery, and under the same tutor, will The hypothesis has seemed convincing to the differ as much from each other as they differ majority of thinkers, but it labors under one fatal "Flachsland rapporte que deux epoux bien constitutes mirent au monde trois enfans sans avant-bras ni jambes; d'autres dont parle Schmucker n'eurent que des enfans munis de douze orteils et douze doigts." -Burdach Traite de Physiologie, ii. 264. vol. ii.; and Serres, "Recherches d'Anatomie TranscenSee Geoffroy St. Hilaire," Philosophic Anatomique,” dante.' +"Physiologie" ii. 245. objection—namely, Species cannot reproduce tion of Species" is absurd, "fixity of Species" itself, for Species does not exist. It is an en- is not a whit less so. That which does not extity, an abstract idea, not a concrete fact. It ist, can neither be transmuted or maintained in is a fiction of the understanding, not an object fixity. Only individuals exist; they resemble existing in Nature. The thing Species no their parents, and they differ from their parents. more exists than the thing Goodness or the Out of these resemblances we create Species, thing Whiteness. Nature only knows individ-out of these differences we create Varieties; uals. A collection of individuals so closely re- we do so as conveniences of classification, and sembling each other as all sheep resemble each then believe in the reality of our own figother, are conveniently classed under one gen- ments. eral term, named species; but this general "Les espèces," said Buffon, boldly, "sont term has no objective existence; the abstract les seuls êtres de la nature," and thousands or typical sheep, apart from all concrete indi- have firmly believed this absurdity. The very viduals, has no existence out of our systems. latest work published on this subject reproduces Whenever an individual sheep is born, it is the the dictum, and elaborately endeavors to dem offspring of two individual sheep, whose struc-onstrate it. "Les espèces sont les formes tures and dispositions it reproduces; it is not primitives de la nature. Les individus n'en the offspring of an abstract idea; it does not sont que des représentations, des copies." This come into being at the bidding of a Type, was very well for Plato; but for a biologist of which as a Species sits apart, regulating ovine the nineteenth century to hold such language phenomena. The facts of dissemblance be- shows a want of philosophic culture. A curtween offspring and parents we shall explain sory survey of the facts should have shown the by-and-by; they do not plead in favor of Spe- error of the conception, if nothing else would. cies, because Species is a figment of philoso- Facts plainly tell us that the individual and the phy, not a fact. The sooner we disengage our individual's peculiarities, not those of the abZoology from all such lingering remains of old stract Type, are transmitted. Plutarch speaks Metaphysics, the better. Nothing but dreary of a family in Thebes, every member of which confusion, and word-splitting can come of our was born with the mark of a spear-head on his admitting them. Think of the hot and unwise body; and although Plutarch is not a good au controversies respecting "transmutation of thority for such a fact, we may accept this bespecies," which would have been spared if a cause it belongs to a class of well authenticated clear conception of the meaning of Species cases. An Italian family had the same sort of had been steadily held before the disputants, mark, and hence bore the name of Lansada. or if the laws which regulate heritage had Haller cites the case of the Bentivoglie family, been duly considered. In one sense, transmu- in whom a slight external tumor was transmittation of Species is a contradiction in terms. ted from father to son, which always swelled To ask if one species can produce another, i.e., when the atmosphere was moist. Again, the a cat produce a monkey-is to ask if the Roman families Nasones and Buccones, indioffspring do not inherit the organization of cate analogous peculiarities; to which may be their parents. We know they do. We cannot added the well-known "Austrian lip" and conceive it otherwise. But the laws of heri-Bourbon nose." All the Barons de Vessins tage place the dispute in something of a clear- were said to have a peculiar mark between er light, for they teach us that "Species" is their shoulders; and by means of such a mark, constant, because individuals reproduce indi-La Tour Landry discovered the posthumous viduals closely resembling them, which is the legitimate son of the Baron de Vessins in a meaning of "Species; and they also teach London shoemaker's apprentice. Such cases us, that individuals reproduce individuals vary might be received with an incredulous smile if ing in structure from themselves, which Varie- they did not belong to a series of indisputable ties, becoming transmitted as part and parcel facts noticed in the breeding of animals. of the parental influence, will, in time, become Every breeder knows that the colors of the so great as to constitute a difference in Species. parents are inherited, that the spots are reIt is in vain that the upholders of "fixity of peated, such as the patch over the bull-terrier's Species" assert, that all the varieties observed eye, and the white legs of a horse or cow; and are differences of degree only. Differences of Chambont lays it down, as a principle derived degree become differences of kind, when the from experience, that by choosing the parents gap is widened; ice and steam are only differences of degree, but they are equivalent to dif-1856. ferences of kind. If, therefore, "transmuta +" Cours de Physiologie Comparee," par M. Flourens. "Traite de l'Education des Moutons," i. 116. you can produce any spots you please. Girou had no sensible effect whatever on them; and noticed that his Swiss cow, white, spotted with Dr. Lucas knows a family upon whom the red, gave five calves, four of which repeated slightest dose of calomel produces violent nerexactly the spots of their mother, the fifth, a vous tremblings. Every physician knows how cow-calf resembling the bull. And do we not both predisposition to and absolute protection all know how successful our cattle-breeders against certain specific diseases are transmithave been in directing the fat to those parts of ted. In many families the teeth and hair fall the organism where gourmandise desires it? out before the ordinary time, no matter what Have not sheep become moving cylinders of hygiène be followed. Sir Henry Holland refat and wool, merely because fat and wool were needed? marks, "The frequency of blindness as a hereditary affection is well-known, whether ocStill more striking are the facts of accidents curring from cataract or other diseases of the becoming hereditary. A superb stallion, son parts concerned in vision. The most remarkaof Le Glorieux, who came from the Pompa- ble of the many examples known to me, is that dour stables, became blind from disease: all his of a family where four out of five children, children became blind before they were three otherwise healthy, became totally blind from years old. Burdach cites the case of a woman amaurosis about the age of twelve; the vision who nearly died from hemorrhage after blood- having been gradually impaired up to this time. letting; her daughter was so sensitive that a What adds to the singularity of this case is violent hæmorrage would follow even a trifling the existence of some family monument long scratch; she, in turn, transmitted this peculi- prior in date, where a female ancestor is rearity to her son. Horses marked during suc- presented with several children around her, cessive generations with red-hot iron in the the inscription recording that all the number same place, transmit the visible traces of such were blind."* But not only are structural pemarks to their colts. A dog had her hinder culiarities transmitted, we see even queer tricks parts paralyzed for several days by a blow; of manner descending to the children. The six of her seven pups were deformed or exces- writer had a puppy, taken from its mother at sively weak in their hinder parts, and were six weeks old, who although never taught "to drowned as useless. Treviranust cites Blum- beg" (an accomplishment his mother had been enbach's case of a man whose little finger was taught), spontaneously took to begging for crushed and twisted, by an accident to his right everything he wanted, when about seven or hand: his sons inherited right hands with the lit- eight months old: he would beg for food, beg tle finger distorted. These cases are the more to be let out of the room, and one day was surprising, because our daily experience also found opposite a rabbit hutch begging for the tells us that accidental defects are not trans-rabbits. Unless we are to suppose all these mitted; for many years it has been the custom cases simple coincidences, we must admit indito cut the ears and tails of terriers, and yet vidual heritage; but the doctrine of probabiliterrier pups do not inherit the pointed ears and ties will not permit us to suppose them coincishort tails of their parents; for centuries men dent. Let us take the idiosyncrasy of cannihave lost arms and legs, without affecting the balism, which may be safely said not to aplimbs of our species. Although, therefore, pear more than once in ten thousand human the deformities and defects of the parent may beings; if, therefore, we take one in ten thoube inherited, in general they are not. For sand as the ratio, the chances against any man our present argument it is enough that they are so sometimes. manifesting the propensity will be ten thousand to one, but the chances against his son also manifesting it will be what, some more learned calculator must declare. Idiosyncrasies assuredly belong to the individual, not to the species; otherwise they would not be idiosyncrasies. Parents with an Not the Species, but the Individual, then, unconquerable aversion to animal food, have we are forced to admit, presides over heritage; transmitted that aversion; and parents with and this will help to explain many puzzling the horrible propensity for human flesh, have phenomena. Thus M. Danney made experitransmitted the propensity to children brought ments during ten years with rabbits, a hundred up away from them under all social restraints. couples being selected by him with a view to Zimmermann cites the case of a whole family the creation of peculiarities. By always upon whom coffee acted like opium, while opium choosing the parents "d'après des circonstances individuelles fixes et toujours les mêmes dans "Medical Notes and Reflections," p. 23. "Girou," p. 127. +"Biologie," iii. 452. certaines lignées," he succeeded in obtaining a Although instincts, in the general acceptanumber of malformations according to his pre- tion of the term, may be said to belong to the conceived plan. And such experiments have species and to be transmitted with the specific been repeated on dogs, pigeons, and poultry type, we have abundant evidence of the indiwith like success. It is on this fact of individual transmission of what are called instincvidual heritage that longevity depends. There tive peculiarities, or acquired habits. Thus is no term of life for the "species," only a Girou relates the case of a sporting dog, taken term for the individual; a fact which sets all young from its mother and father, who was sinthe speculations of Cornaro, Hufeland, and gularly obstinate, and exhibited the greatest Flourens at naught. There are limits which terror at every explosion of the gun, which alneither the "species nor the individual can ways excites the ardor of the species. On be said to pass; no man has been known to the owner expressing his surprise to the gen live two hundred years; but the number of tleman from whom he received the dog, he years which each individual will reach, without was told that nothing was more likely, for the accident, is a term depending neither on the dog's father had the same peculiarity. How "species," nor on his own mode of life, but on the vicious disposition of horses is transmitted, the organization inherited from his parents. all breeders know. Again, we know that the Temperance, sobriety, and chastity, however vice of drunkenness is very apt to be inherit desirable, both in themselves and in their ef- ed; and that the passion for gambling is little fects, will not insure long life; intemperance, less so. "A lady with whom I was very inhardship, and irregularity will not prevent a timate," relates Da Gama Machado," and who man living for a century and a half. The facts possessed great wealth, passed her nights in are there to prove both propositions. Longevity is an inheritance. Like talent, it may be cultivated; like talent, it may be perverted but it exists independent of all cultivation, and no cultivation will create it. Some men have a talent for long life. his The gaming; she died young from pulmonary disease. Her eldest son was equally addicted to play, and he also died of consumption at the same age as his mother. His daughter inherited the same passion and the same disease." Other and more crapulous vices are inherited, M. Charles Lejoncourt published, in 1842, and are exhibited in cases where the early Galerie des Centenaires, in which may be death of the parents, or the removal of the read a curious list of examples proving the children in infancy, prevents the idea of any hereditary nature of longevity. In one page imitation or effect of education being the cause. we have a day laborer dying at the age of 108, That the "thieving propensity" is transmitted his father lived to 104, his grandfather to 108, from father to son through generations, all acand his daughter then living had reached 80. quainted with police-courts know. Gallt has In another we have a saddler whose grand- cited some striking examples; and that murfather died at 112, his father at 113, and he der, like talent, runs in families, is too notorious himself at 115; this man, aged 113, was asked to need illustrations here. Dogs taught to by Louis XIV. what he had done to so prolong "point" or "set," transmit the talent. life; his answer was-"Sire, since I was fif- American dogs inherit the peculiar cunning ty I have acted upon two principles; I have necessary to hunt the peccari without danger. shut my heart and opened my wine cellar." F. Cuvier has observed that young foxes, in M. Lejoncourt also mentions a woman then liv- those parts of the country where traps are set, ing, aged 150, whose father died at 124, and manifest much more prudence than even the whose uncle at 113. But the most surprising old foxes in districts where they are less perseof the cases cited by Lucas, is that of Jean cuted. Again, birds born in a country inhab Golembiewski, a Pole, who in 1846 was still ited by man inherit their alarm at his presence; living, aged 102, having been eighty years as but travellers narrate that the same species ena common soldier, in thirty-five campaigns un- countered on uninhabited islands manifest no der Napoleon, and having even survived the alarm, and are knocked down as easily as a terrible Russian campaign, in spite of five gentleman in Fleet street; they soon, however, wounds, and a soldier's recklessness of life. learn to dread man, and this dread they transHis father died aged 121, and his grandfather, mit. As these last illustrations may be relegated 130. Indeed, the practice of every annuity to the vague region of instincts, we will conand insurance office suffices to convince us of fine ourselves to more individual and accidenordinary experience having discovered that tal characteristics. Thus Girou relates how a length of life is somehow dependent on heredi-l "Theorie des Ressemblances," p. 154, quoted by Lucas. tary influence. +"Fonctions du Cerveau," i. 207. |