No. 4746.

AUGUST 15, 1914.

ABSTRACT OF

A Presidential AddressON

HEREDITY.Delivered in Melbourne on August 14th, 1914, before the

Meeting of the British Association for the Advance-ment of Science,

BY WILLIAM BATESON, M.A., F.R.S.,PRESIDENT OF THE ASSOCIATION.

GENTLEMEN,-I shall attempt to give the essenceof the discoveries made by Mendelian or analyticalmethods of study and ask you to contemplate thedeductions which these physiological facts suggestin application both to evolutionary theory at largeand to the special case of the natural history ofhuman society. Recognition of the significanceof heredity is modern. The term itself in itsscientific sense is no older than Herbert Spencer.Animals and plants are formed as pieces of

living material split from the body of the parentorganisms. Their powers and faculties are fixedin their physiological origin. They are the con-

sequence of a genetic process, and yet it is only latelythat this genetic process has become the subject ofsystematic research and experiment. The curiosityof naturalists has of course always been attractedto such problems; but that accurate knowledge ofgenetics is of paramount importance in any attemptto understand the nature of living things has onlybeen realised quite lately even by naturalists, andwith casual exceptions the laity still know nothingof the matter. Historians debate the past of thehuman species, and statesmen order its present orprofess to guide its future as if the animal man,the unit of their calculations, with his vast diversityof powers, were a homogeneous material which canbe multiplied like shot.The reason for this neglect lies in ignorance and

misunderstanding of the nature of variation; fornot until the fact of congenital diversity is grasped,with all that it imports, does knowledge of the

system of hereditary transmission stand out as aprimary necessity in the construction of any theoryof evolution, or any scheme of human polity.The first full perception of the significance of

variation we owe to Darwin. The present genera-tion of evolutionists realises perhaps more fullythan did the scientific world in the last centurythat the theory of evolution had occupied thethoughts of many and found acceptance with nota few before ever the Origin" appeared. We have Icome also to the conviction that the principle ofnatural selection cannot have been the chief factorin delimiting the species of animals and plants,such as we now with fuller knowledge see themactually to be. We are even more sceptical as tothe validity of that appeal to changes in the con-ditions of life as direct causes of modification, uponwhich latterly at all events Darwin laid much- emphasis. But that he was the first to providea body of fact demonstrating the variability ofliving things, whatever be its causation, can neverbe questioned.

[Professor Bateson, having premised that formerlyit was hoped that by the simple inspection of,embryological processes the modes of hereditymight be ascertained and the actual mechanism bywhich the offspring is formed from the body of the

parent be arrived at, then said that so long as noone can show consistent distinctions between thecytological characters of somatic tissues in thesame individual, distinctions between the chromo-somes of the various types cannot be perceived.Hence, for the old methods of attack, he said, therehas been substituted the breaking up of the main

6 problem into its parts, such analytical studybeing called Mendelian because Mendel was thefirst to apply it. He pointed out that misconcep-tion was especially brought in by describing descentin terms of blood, truer notions of genetic physio-logy being given by the Hebrew expression " seed."]

THE FACTORS IN THE TRANSMISSION OFCHARACTERISTICS.

The allotment of characteristics among offspringis not accomplished by the exudation of drops of atincture representing the sum of the characteristicsof the parent organism, but by a process of cell-division, in which numbers of these characters, orrather the elements upon which they depend, aresorted out among the resulting germ cells in anorderly fashion. What these elements, or factorsas we call them, are we do not know. That theyare in some way directly transmitted by the materialof the ovum and of the spermatozoon is obvious,but it seems to me unlikely that they are in anysimple or literal sense material particles. I suspectrather that their properties depend on some

phenomenon of arrangement. However that maybe, analytical breeding proves that it is according tothe distribution of these genetic factors, to use a non-committal term, that the characters of the offspringare decided. The first business of experimental gene-tics is to determine their number and interactions,and then to make an analysis of the various typesof life. The ordinary genealogical trees, such asthose which the stud-books provide in the case ofthe domestic animals, or the Heralds’ College pro-vides in the case of man, tell nothing of all this.Such methods of depicting descent cannot evenshow the one thing they are devised to show-purity of

" blood." For at last we know the physio-

logical meaning of that expression. An organism ispure-bred when it has been formed by the union intertilisation of two germ cells which are alike inthe factors they bear; and since the factors for theseveral characteristics are independent of eachother, this question of purity must be separatelyconsidered for each of them. A man, for example,may be pure-bred in respect of his musical abilityand cross-bred in respect of the colour ofhis eyes or the shape of his mouth. Thoughwe know nothing of the essential nature ofthese factors, we know a good deal of theirpowers. They may confer height, colour, shape,instincts, powers both of mind and body; indeed,so many of the attributes which animals and plantspossess that we feel justified in the expectation thatwith continued analysis they will be proved to beresponsible for most if not all of the differences bywhich the varying individuals of any species aredistinguished from each other.

Professoi Bateson then summarised the mainfeatures of the work that has been done to showthat the great differences which characterisedistinct species are due generally to such

independent factors, the essential principle beingthat an organism cannot pass on to its off-

spring a factor which it has not itself receivedin fertilisation. He proceeded :]Parents which are both destitute of a given

factor can o7ly produce offspring equallyG

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destitute of it, and parents both pure-bred for thepresence of a factor produce offspring equally pure-bred for its presence. Whereas the germ cells of thepure-bred are all alike, those of the cross-bred, owingto the union of dissimilar germ cells, are mixedin character. Each positive factor segregates fromits negative opposite, so that some germ cells carrythe factor and some do not. Once the factors havebeen identified by their effects the average com-position of the several kinds of families formedfrom the various matings can be predicted. The

body of evidence accumulated by this method ofanalysis is indeed very large, and progress isbeginning along many novel and curious lines.

THE DOCTRINE OF SURVIVAL OF THE FITTEST.

In face of what we now know of the distributionof variability in nature the scope claimed fornatural selection in determining the fixity of

species must be greatly reduced. The doctrine ofthe survival of the fittest is undeniable so long asit is applied to the organism as a whole, but toattempt by this principle to find value in alldefiniteness of parts and functions, and in the nameof science to see fitness everywhere is mere

eighteenth century optimism. Yet it was in appli-cation to the parts, to the details of specificdifference, to the spots on the peacock’s tail, to thecolouring of an orchid flower, and hosts of suchexamples, that the potency of natural selection wasurged with the strongest emphasis. Shorn of thesepretensions the doctrine of the survival of favouredraces is a truism, helping scarcely at all to accountfor the diversity of species. Tolerance plays almostas considerable a part. By these admissions almostthe last shred of that teleological fustian withwhich Victorian philosophy loved to clothe the

theory of evolution is destroyed. Those who wouldproclaim that whatever is is right will be wisehenceforth to base this faith frankly on the

impregnable rock of superstition and to abstainfrom direct appeals to natural fact.My predecessor said last year that in physics the

age is one of rapid progress and profound scepticism.In at least as high a degree this is true of biology, Iand as a chief characteristic of modern evolutionarythought we must confess also to a deep but irksome ihumility in presence of great vital problems. Every ’’,theory of evolution must be such as to accord withthe facts of physics and chemistry, a primary ’,necessity to which our predecessors paid small heed.For them the unknown was a rich mine of possi-bilities on which they could freely draw. For us itis rather an impenetrable mountain out of whichthe truth can be chipped in rare and isolatedfragments. Of the physics and chemistry of life weknow next to nothing. Somehow the characters of

living things are bound up in properties of colloids,and are largely determined by the chemical powersof enzymes, but the study of these classes of matterhas only just begun. Living things are found

by a simple experiment to have powers undreamtof, and who knows what may be behind?

THE PROBLEM OF VARIATION.

Naturally we turn aside from generalities. It isno time to discuss the origin of the moHusca or ofdicotyledons, while we are not even sure how itcame to pass that Primula obconica has in 25 yearsproduced its abundant new forms almost under oureyes. Knowledge of heredity has so reacted on ourconceptions of variation that very competent menare even denying that variation in the old senseis a genuine occurrence at all. Variation is

postulated as the basis of all evolutionary change.Do we then as a matter of fact find in the worldabout us variations occurring of such a kind as towarrant faith in a contemporary progressive evolu-tion ? Till lately most of us would have said " Yes’7 ’’

without misgiving. We should have pointed, asDarwin did, to the immense range of diversity seenin many wild species, so commc nly that the difficultyis to define the types themselves. Still more con-clusive seemed the profusion of forms in the

various domesticated animals and plants, most ofthem incapable of existing even for a generationin the wild state, and therefore fixed unquestion-ably by human selection. These, at least, for-certain, are new forms, often distinct enough to.

pass for species, which have arisen by variation.But when analysis is applied to this mass ofvariation the matter wears a different aspect.Closely examined, what is the

"

variability" of wildspecies ? What is the natural fact which isdenoted by the statement that a given speciesexhibits much variation? Generally one of two.

things: either that the individuals collected in one-locality differ among themselves ; or perhaps moreoften that samples from separate localities differfrom each other. As direct evidence of variation itis clearly to the first of these phenomena that wemust have recourse-the heterogeneity of a popula-tion breeding together in one area. This hetero-

geneity may be in any degree, ranging from slightdifferences that systematists would disregard to acomplex variability such as we find in some moths,where there is an abundance of varieties so distinctthat many would be classified as specific forms butfor the fact that all are freely breeding together.Naturalists formerly supposed that any of thesevarieties might be bred from any of the others.Just as the reader of novels is prepared to find thatany kind of parents might have any kind of childrenin the course of the story, so was the evolutionistready to believe that any pair of moths mightproduce any of the varieties included in the species.Genetic analysis has disposed of all these mistakes.We have no longer the smallest doubt that in allthese examples the varieties stand in a regulardescending order, and that they are simply termsin a series of combinations of factors separatelytransmitted, of which each may be present or-

absent.

The appearance of contemporary variabilityproves to be an illusion. Variation from step to.step in the series must occur either by the additionor by the loss of a factor. Now, of the origin of £ new forms by loss there seems to me to be fairlyclear evidence, but of the contemporary aequisitionof any new factor I see no satisfactory proof, thoughI admit there are rare examples which may be so>

interpreted. We are left with a picture of variationutterly different from that which we saw at first.Variation now stands out as a definite physiologicalevent. We have done with the notion thatDarwin came latterly to favour, that large-differences can arise by accumulation of smalldifferences. Such small differences are often mereephemeral effects of conditions of life, and as suchare not transmissible ; but even small differences,when truly genetic, are factorial like the largerones, and there is not the slightest reason forsupposing that they are capable of summation. As.to the origin or source of these positive separablefactors, we are without any indication or surmise.By their effects we know them to be definite, asdefinite, say, as the organisms which produce

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diseases; but how they arise and how they cometo take part in the composition of the livingcreature so that when present they are treated incell-division as constituents of the germs we cannotconjecture.

THE PART PLAYED BY CROSS-BREEDING.

tprof essor Bateson then reviewed the evidence fordisbelieving in the common theory that domestic- animals have been developed from a few wild types.He showed that it was hopeless to reconstruct the;steps in evolution of various forms of fowls fromthe Indian jungle fowl, while most of the newvarieties of cultivated plants are, he said, theoutcome of deliberate crossing, for we have fullhistories of these crosses in gladiolus, orchids,- cineraria, begonia, calceolaria, and pelargonium.The single origins presumed for dogs, horses, cattle,sheep, poultry, wheat, oats, rice, plums, and cherrieshave in turn failed to stand investigation, the dis-tinctions between the chief varieties being traceableas far back as evidence reaches.] Once it is known,be said, that the supposed intergrades are merelymongrels between the two species, the transitionrom one to the other is practically beyond ourpowers of imagination. If both these can survive,why has their common parent perished ? Why whenthey cross do not they reconstruct it instead of

producing partially sterile hybrids ? When once theidea of a true-breeding-or, as we say, homozygous-type is grasped, the problem of variation becomesan insistent oppression. What can make such a

type vary ? We know, of course, one way by whichnovelty can be introduced-by crossing. Cross two

, well-marked varieties-for instance, of Chineseprimula-each breeding true, and in the secondgeneration by mere recombination of the variousfactors which the two parental types severallyintroduced, there will be a profusion of forms,utterly unlike each other, distinct also fromthe original parents. Many of these can be bredtrue, and if found wild would certainly be describedas good species. Confronted by the difficulty I haveput before you, and contemplating such amazingpolymorphism in the second generation from a

.cross in antirrhinum, Lotsy has lately with greatcourage suggested to us that all variation may bedue to such crossing. I do not disguise my sym-pathy with this effort. After the blind com-

placency of conventional evolutionists it isrefreshing to meet so frank an acknowledgmentof the hardness of the problem. Lotsy’s utterancewill at least do something to expose the artificialityof systematic zoology and botany. Whatever mightor might not be revealed by experimental breed-ing, it is certain that without such tests weare merely guessing when we profess to distin-guish specific limits and to declare that this is aspecies and that a variety. The only definable unitin classification is the homozygous form whichbreeds true. When we presume to say that suchand such differences are trivial and such othersvalid, we are commonly embarking on a coursefor which there is no physiological warrant. Whocould have foreseen that the apple and the pear-so like each other that their botanical differencesare evasive-could not be crossed together, though-species of antirrhinum so totally unlike each otheras majits and molle can be hybridised, as Baur has;shown, without a sign of impaired fertility ? Jordanwas perfectly right. The true-breeding forms which Ihe distinguished in such multitudes are real Ientities, though the great systematists, dispensingwith such laborious analysis, have pooled them into

arbitrary Linnsean species, for the convenience ofcollectors and for the simplification of catalogues.Such pragmatical considerations may mean muchin the museum, but with them the student of thephysiology of variation has nothing to do. These" little species," finely cut, true-breeding, andinnumerable mongrels between them, are what hefinds when he examines any so-called variabletype. On analysis the semblance of variabilitydisappears, and the illusion is shown to be due to

segregation and recombination of series of factorson pre-determined lines. As soon as the " littlespecies " are separated out they are found to befixed. In face of such a result we may well askwith Lotsy, Is there such a thing as spontaneousvariation anywhere 2 His answer is that there isnot.

VARIATION BY LOSS OF FACTOR.

Abandoning the attempt to show that positivefactors can be added to the original stock, we havefurther to confess that we cannot often actuallyprove variation by loss of factor to be a real

phenomenon. Lotsy doubts whether even thisphenomenon occurs. The sole source of variation,in his view, is crossing. But here I think he is onunsafe ground. When a well-established varietylike " Crimson King" primula, bred by Messrs.Sutton in thousands of individuals, gives off,as it did a few years since, a salmon-coloured

variety, " Coral King," we might claim this as a

genuine example of variation by loss. The newvariety is a simple recessive. It differs from" Crimson King " only in one respect, the loss of a

single colour-factor, and, of course, breeds true fromits origin. To account for the appearance of sucha new form by any process of crossing is ex-

ceedingly difficult. From the nature of the case

there can have been n0 cross since " CrimsonKing " was established, and hence the salmon musthave been concealed as a recessive from the first

origin of that variety, even when it was repre-sented by very few individuals, probably only by asingle one. Surely, if any of these had been

heterozygous for salmon this recessive could

hardly have failed to appear during the processof self-fertilisation by which the stock would bemultiplied, even though that selfing may not havebeen strictly carried out. Examples like this seemto me practically conclusive. They can be chal-

lenged, but not, I think, successfully. Then, again,in regard to those variations in number and divisionof parts which we call meristic, the reference ofthese to original cross-breeding is surely barredby the circumstances in which they often occur.

There remain also the rare examples mentionedalready in which a single wild origin may withmuch confidence be assumed. In spite of repeatedtrials, no one has yet succeeded in crossing thesweet pea with any other leguminous species.We know that early in its cultivated historyit produced at least two marked varieties whichI can only conceive of as spontaneously arising,though, no doubt, the profusion of forms wenow have was made by the crossing of thoseoriginal varieties. I mention the sweet peathus prominently for another reason-that itintroduces us to another though subsidiaryform of variation, which may be described as a

fractionation of factors. Some of my Mendelian

colleagues have spoken of genetic factors as

permanent and indestructible. Relative permanencein a sense they have, for they commonly come outunchanged after segregation. But I am satisfied

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that they may occasionally undergo a quantitativedisintegration, with the consequence that varietiesare produced intermediate between the integralvarieties from which they were derived. Thesedisintegrated conditions I have spoken of as sub-traction-or reduction-stages. For example, thepicotee sweet pea, with its purple edges, can surelybe nothing but a condition produced by the

factor which ordinarily makes the fully purpleflower, quantitatively diminished. The pied animal,such as the Dutch rabbit, must similarly be regardedas the result of partial defect of the chromogenfrom which the pigment is formed, or conceivablyof the factor which effects its oxidation. On suchlines I think we may with great confidence interpretall these intergrading forms which breed true andare not produced by factorial interference.

THE COURSE OF EVOLUTION.

[Professor Bateson then inferred that these frac-tional degradations are the consequence of irregu-larities in segregation, and gave evidence of

departures from normal regularity in the rhythmsof repetition or waves of differentiation b3 whichqualities are sorted out among parts of the body.He said that he felt no reasonable doubt thatthough we may have to forego a plan of variationsby addition of factors, variation both by loss offactors and fractionation of factors is a genuinephenomenon of contemporary nature. If we haveto dispense, as seems likely, with any addition fromwithout, we must begin seriously to considerwhether the course of evolution can at all reason-ably be represented as an unpacking of an originalcomplex which contains within itself the wholerange of diversity which living things present." Hepropounded no theory of evolution, but pointed outthat, as we have got to recognise that there hasbeen an evolution and that somehow or other theforms of life have arisen from fewer forms, we mayas well see whether we are limited to the old viewthat evolutionary progress is from the simple to thecomplex, and whether after all it is conceivablethat the process was the other way about.]We have to reverse our habitual modes of thought.

At first it may seem rank absurdity to suppose thatthe primordial form or forms of protoplasm couldhave contained complexity enough to produce thedivers types of life. But is it easier to imagine thatthese powers could have been conveyed by extrinsicadditions ? Of what nature could these additionsbe ? Additions of material cannot surely be in

question. We are told that salts of iron in the soilmay turn a pink hydrangea blue. The iron cannotbe passed on to the next generation. How can theiron multiply itself ? The power to assimilate theiron is all that can be transmitted. A disease-producing organism like the pebrine of silkwormscan in a very few cases be passed on through thegerm cells. Such an organism can multiply and can

Iproduce its characteristic effects in the next genera- Ition. But it does not become part of the invaded host,and we cannot conceive it taking part in the geo-metrically ordered processes of segregation. Theseillustrations may seem too gross ; but what refine-ment will meet the requirements of the problem,that the thing introduced must be, as the livingorganism itself is, capable of multiplication and ofsubordinating itself in a definite system of segrega-tion ? That which is conferred in variation mustrather itself be a change, not of material, but ofarrangement, or of motion. The invocation ofadditions extrinsic to the organism does notseriously help us to imagine how the power to

change can be conferred, and if it proves that hopein that direction must be abandoned I think welose very little. By the re-arrangement of a verymoderate number of things we soon reach a numberof possibilities practically infinite." RELEASES " OF POWERS NORMALLY SUPPRESSED.That primordial life may have been of small

dimensions need not disturb us. Quantity is of noaccount in these considerations. Shakespeare onceexisted as a speck of protoplasm not so big as asmall pin’s head. To this nothing was added thatwould not equally well have served to build up a.baboon or a rat. Let us consider how far we can

get by the process of removal of what we call"

epistatic" factors-in other words, those thatcontrol, mask, or suppress underlying powers andfaculties. I have spoken of the vast range ofcolours exhibited by modern sweet peas. There isno question that these have been derived from theone wild bi-colour form by a process of successiveremovals. When the vast range of form, size, andflavour to be found among the cultivated apples isconsidered, it seems difficult to suppose that allthis variety is hidden in the wild crab-apple. Icannot positively assert that this is so, butI think all familiar with Mendelian analysiswould agree with me that it is probable,and that the wild crab contains presumablyinhibiting elements which the cultivated kindshave lost. The legend that the seedlings ofcultivated apples become crabs is often repeated.After many inquiries among the raisers of appleseedlings I have never found an authentic case- .once only even an alleged case-and this on inquiryproved to be unfounded. I have confidence thatthe artistic gifts of mankind will prove to be due,not to something added to the make-up of an

ordinary man, but to the absence of factors whichin the normal person inhibit the development ofthese gifts. They are almost beyond doubt to belooked upon as 1’eZeases of powers normally sup-pressed. The instrument is there, but it is "stoppeddown." The scents of flowers or fruits, the finelyrepeated divisions that give its quality to the woolof the merino, or in an analogous case the multi-plicity of quills to the tail of the fantail pigeon, arein all probability other examples of such releases.You may ask what guides us in the discrimination ofthe positive factors and how we can satisfy ourselvesthat the appearance of a quality is due to loss. Itmust be conceded that in these determinations wehave as yet recourse only to the effects of dominance.When the tall pea is crossed with the dwarf, sincethe offspring is tall we say that the tall parentpassed a factor into the cross-bred which makes ittall. The pure tall parent had two doses of this.factor, the dwarf had none ; and since the cross-bred is tall we say that one dose of the dominanttallness is enough to give the full height. The

reasoning seems unanswerable. But the commonerresult of crossing is the production of a formintermediate between the two pure parental types.In such examples we see clearly enough that thefull parental characteristics can only appear whenthey are homozygous-formed from similar germ-cells, and that one dose is insufficient to produceeither effect fully. When this is so we can neverbe sure which side is positive and which negative.Since, then, when dominance is incomplete we findourselves in this difficulty, we perceive that theamount of the effect is our only criterion in dis-tinguishing the positive from the negative, andwhen we return even to the example of the tall and

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dwarf peas the matter is not so certain as itseemed.

[Professor Bateson here quoted Cockerill’s experi-ments with sunflowers, where among thousands ofyellow flowers one occurred partly red, by breedingfrom which a form wholly red was raised, andasked if we could not interpret other apparent newdominants in the same way. The white dominantin the fowl or in the Chinese primula can inhibitcolour. He asked, May it not be that the originalfowl or primula had two doses of a factor whichinhibited this inhibitor ? In 1840 the pepper mothproduced a black variety now common in certainareas and behaving as a full dominant. The pureblacks are no blacker than the cross-bred. Thoughat first sight it seems that the black must have beensomething added, we can without absurdity suggestthat the normal is the term in which two dosesof inhibitor are present, and that in the absence ofone of them the black appears.]

SUMMARY OF DEDUCTIONS.

In spite of seeming perversity, therefore, we haveto admit that there is no evolutionary change whichin the present state of our knowledge we can posi-tively declare to be not due to loss. When this hasbeen conceded it is natural to ask whether theremoval of inhibiting factors may not be invokedin alleviation of the necessity which has drivenstudents of the domestic breeds to refer theirdiversities to multiple origins. Something, nodoubt, is to be hoped for in that direction, but notuntil much better and more extensive knowledge ofwhat variation by loss may effect in the living bodycan we have any real assurance that this difficultyhas been obviated. We should be greatly helped bysome indication as to whether the origin of life hasbeen single or multiple. As the evidence stands atpresent, all that can be safely added in amplificationof the evolutionary creed may be summed upin the statement that variation occurs as a

definite event often producing a sensibly discon-tinuous result; that the succession of varieties comesto pass by the elevation and establishment of

sporadic groups of individuals owing their origin tosuch isolated events ; and that the change whichwe see as a nascent variation is often, perhapsalways, one of loss. Modern research lends not thesmallest encouragement or sanction to the viewthat gradual evolution occurs by the transforma-tion of masses of individuals, though that fancy hasfixed itself on popular imagination. The isolatedevents to which variation is due are evidentlychanges in the germinal tissues, probably in themanner in which they divide. It is likely thatthe occurrence of these variations is whollyirregular, and as to their causation we e are

absolutely without surmise or even plausiblespeculation. Distinct types once arisen, no doubta profusion of the forms called species havebeen derived from them by simple crossing andsubsequent recombination. New species may benow in course of creation by this means, but thelimits of the process are obviously narrow. On theother hand, we see no changes in progress aroundus in the contemporary world which we can imaginelikely to culminate in the evolution of formsdistinct in the larger sense. By intercrossing dogs,jackals, and wolves new forms of these types canbe made, some of which may be species, but I seeno reason to think that from such material a foxcould be bred in indefinite time, or that dogs couldbe bred from foxes.

Whether science will hereafter discover thatcertain groups can by peculiarities in their geneticphysiology be declared to have a prerogativequality justifying their recognition as species in theold sense, and that the differences of others are ofsuch a subordinate degree that they may in contrastbe termed varieties, further genetic research alonecan show. I myself anticipate that such a discoverywill be made, but I cannot defend the opinion withpositive conviction.Somewhat reluctantly and rather from a sense of

duty, I have devoted most of this address to theevolutionary aspects of genetic research. We cannotkeep these things out of our heads, though sometimeswe wish we could. The outcome, as you will haveseen, is negative, destroying much that till latelypassed for gospel. Destruction may be useful, butit is a low kind of work. We are just about whereBoyle was in the seventeenth century. We can

dispose of alchemy, but we cannot make more thana quasi-chemistry. We are awaiting our Priestleyand our Mendeleeff. In truth, it is not these wideraspects of genetics that are at present our chiefconcern. They will come in their time. The greatadvances of science are made like those of evolu-tion, not by imperceptible mass-improvement, butby the sporadic birth of penetrative genius. Thejourneymen follow after him, widening and clearingup, as we are doing along the track that Mendelfound.

CONGENITAL ATRESIA OF THE POST-NASAL ORIFICE.1

BY CHARLES W. RICHARDSON, M.D.

THE occurrence of congenital obstruction to thepost-nasal orifice is described by many writers as avery infrequent form of nasal deformity, but whenwe consider the number of cases reported one

cannot but be impressed with the relative fre-

quency of this type of nasal obstruction. Indeed,it seems to me to be one of the most frequent typesof congenital malformation in the nasal chambers.To be sure, seldom does it become the fortuneof a rhinologist to see more than one example ofthis type of malformation, and many with largeexperience have never seen a single case. Onemust also consider the possibility that many casesof this kind of deformity have been in the past, andeven at the present time are unrecognised at birthas such, and when speedily dying, as a result of theobstruction to respiration, are placed under thegeneral class of asphyxia neonatorum. If all cases ofasphyxia neonatorum were properly differentiated,as they probably will be in the future, we will prob-ably find that this form of deformity is responsiblefor no small proportion of these cases. As manyobservers have noted, the number of observed casesin children and adults has increased greatly duringthe past 20 years, largely due to the increasednumber of intelligent workers in rhinology, themore exact and thorough examination of patients,and from the knowledge more widely diffused thatsuch a deformity may occur. The number of casesobserved in the newly born has not increased inthe same proportion as the cases observed later inlife. I believe that this is due to the fact thatthe general practitioner and the obstetrician underwhose observation the infants are first brought

1 A paper read before the Clinical Congress of Surgeons of NorthAmerica, London, July 28th, 1914.