The historiography of genetics is not very extensive. As a tribute to Gregor Mendel the Genesis of modern Genetics is briefly described in its full range, from the Paleolithic Age to Lysenko. Since the earliest times, the knowledge of heredity had been growing in proportion with the development of ideas on reproduction and continuity of the species. For various forms of life, the basic problems of interest remained essentially the same during all historical periods; only the emphasis shifted from the gross to the more detailed, and the answers oscillated between the theories of preformation and epigenesis. Against this historical background, Mendel and the Mendelian laws stand out as the basic foundation of genetics.

The vital growing ideas on generation and evolution of plants, animals, and man are briefly reviewed and exposed as they had occurred before and after Mendel. The historical sketch leads us to ancient Assyria, India, the biblical times, and the classical Antiquity, to the early Greek philosophers and physicians whose works are sampled to illustrate the ancient beliefs concerning the role of male and female semen in generation, and concerning the proportional share of parents in the formation of body and mind of the offspring. The medieval knowledge on heredity is at its highest in the writings of Albertus Magnus whose work represents the refinement of scholastic science.

In these earlier times people did not know the exact functions of the organs of generation, or the true nature of sex. After the invention of the microscope in the 16th, and with a more liberal spirit of research in the 17th centuries, the sexual life and the male and female germ cells of many bisexual beings, including man, were gradually discovered during the 200-year period from 1677 to 1877. This happened with all sorts of speculation about heredity and about the origin and evolution of life. Meanwhile, many practical and theoretical hybridizers saw the various peculiarities in the filial generations, and many observed normal and abnormal characters transmitted from parents to offspring. Yet, none could formulate these observations into a mathematical regularity of inheritance until the reports of Gregor Mendel in 1865 on the result of his plant-crossings.

His discovery was buried, however, until 1900 when other biologists came to the same results, and revived and accepted his rules as the laws of heredity. From then on, modern genetics advanced rapidly and branched into many activities, everywhere fully supporting the views of Mendel. Thus, Mendel is truly the father of genetics, except for communist Russians whose political theories demand the denial of Mendelian heredity and the adherence to older discarded theories.

Genetics has the destiny to solve many practical problems in the life of nations, and to investigate a number of important yet unknown factors, in order to utilize the gene theory of heredity, and the “nuclear energy”, for a wider and brighter service of humanity.

Die Verfasser berichten ausführlich über einen seltenen Familienbefund einer osteogenesis imperfecta tarda bei einer fünfzigjährigen Frau und ihren beiden Zwillingstöchtern, MZ, im Alter von zwanzig Jahren. Dieser neue veröffentlichte Fall bestätigt die Erblichkeit der Krankheit und ihren dominanten Charakter; ausserdem zeugt er von einem hohen Durchdringungsvermögen und der Möglichkeit eines Familienmerkmals, welches — vie im vorliegenden Falle — in einem Vorwiegen der Plastizität über die Zerbrechlichkeit der Knochen und in fehlender Otosklerose besteht.

Beim Skelett der Zwillinge bemerkt man ausserdem — im Gegensatz zur Mutter — Zonen von Knochenverdìchtung (lokalisierte, sekundäre Osteosklerose); und zwar an ähnlichen Stellen, was darauf schliessen lässt, dass sie genotypisch bedingt sind, obwohl dieses ein ungewöhnliches Symptom ist.

Two monozygous twin girls, now 7 years old, with complete concordance of an almost total universal albinism were found in an « isolate » near Aosta in the Western Italian Alps. Their parents show normal pigmentation, and are first cousins, their common grandmothers having a brother who was the grandfather of another albinotic girl, aged 22. The parents of the latter were examined by the Dutch ophthalmogeneticist P. J. Waardenburg: while her father did not show definitely diaphane irides, her mother did. As a similar discrepancy in otherwise normal parents of albinos was stated in 2 more families (Hanhart 1952), the presence of diaphane or not diaphane irides cannot be regarded as sufficient symptom to distinguish two different biotypes of simple-recessive universal albinism. Heterogeny, though rather probable, of this character has not yet been proved in white man.

In Switzerland, and Italy as well, there are considerable local accumulations of universal albinism, so that calculations on the basis of a medium frequency do not hold. The percentage of 7.9 for first cousin marriages of normal parents of albinotic children and 8% for second cousins can hardly be taken as a proof for heterogeny of the gene concerned.

The observation of monozygous twins with concordant universal albinism is the first made in Europe, and the third published all over the world. It is unique on account of the near consanguinity of the normal parents of these twins. Its incidence in Northern Italy speaks in favour of a relatively frequent occurrence of this character in this country, suggested already by the author's population studies.

New data on the heredity of the M-N types in 420 families with 645 children conform precisely with the requirements of the genetic theory of Landsteiner and Levine. To date as many as 1580 families with 3379 children have been tested in our laboratory. According to our experiences, the three M-N types are entirely reliable for use in medicolegal cases of disputed paternity, provided that the individual who performs the tests is qualified.

New data on the distribution of the M-N types in 954 individuals are presented, as well as data on the distribution of the M-N S types in 394 individuals. The findings regarding the M-N-S types agree with previous reports concerning their distribution in Caucasoids. The medicolegal application of the M-N-S types is discussed and it is pointed out that more work must be done before the S and s factors can be safely used. What is needed most is methods for preparing anti-S and anti-s sera of satisfactory specificity and avidity.

A certain amount of material is provided for studying the heredity of fissures of the iris, and it seems that such a heredity is probably not of monohybrid nature. The relationship between fissures and pigmentation of the iris has been confirmed and noted also by earlier researches. This connection may be explained by the fact that fissures of the iris-appearing even earlier, during embriological development—leave fewer chromatophores in the stratum limitans anterior for the formation of pigment. It thus follows that the colour of the iris, which is determined by comparing it with table of colours of the eye, would not be of monohybrid heredity. It is doubtful even when both colour and structure of the iris are contemporaneously studied in order to realise a polysymptomatic resemblance—as for the diagnosis of monovular twins of the diagnostic of paternity—since the logical basis for establishing a polysymptomatic comparison of resemblance is, in fact, given by the independance of partial signs connected one with another. This goes for all cases, whether or no statistical methods are used for the critical examination of such researches, such as, for example, Essen-Möller's formula (3,4) (Wichmann 22, 23).

The present work deals with the question of the heredity of intracranial tumours, the twin method constituting hereby the basis for investigation.

1. In an unselected series of twins collected from the Psychiatric and Neurological Clinic of the university of Münster (Psychiatrische und Nervenklinik der Universität Münster) in the case of seven examined pairs of twins (3 monozygotic, 4 dizygotic: like sex and unlike sex) manifestation of cerebral tumours is dissimilar (table II).

2. This unselected series combined with previous casuistic reports published until now in world literature (table I) of twins with cerebral tumours has not yet brought a sufficient basis for definite genetic conclusion. The question of inheritance in cerebral tumours will only be elucidated by procuring and reviewing material from a larger unselected series of twin patients afflicted with cerebral tumours.

Clinical and histopathological data are presented on monozygotic twin sisters concordant as to schizophrenia, Morgagni's syndrome, and adenomatous goiter. The association of the three traits may have been coincidental, but apparently had a common denominator. The genetic theory of Morgagni's syndrome (pointing to autosomal dominance with irregular penetrance and especially low manifestation in the male) is discussed.

Im folgenden soil über die Ergebnisse von systematischen Familienuntersuchungen berichtet werden, die ich bei unausgelesenen totgeborenen und im ersten Lebenshalbjahr verstorbenen Kindern mit letalen Anomalien der Körperform durchführen konnte.

Der Begriff « Anomalien der Körperform » wird dabei im Sinne meines Lehrers v. Verschuer für typische, oft erbliche Missbildungen einschliesslich Kombinationsmissbildungen mit Veränderung der äusseren Körperform gebraucht, die ich als Todesursache unter den in den Jahren 1937-39 im Pathologischen Institut der Universität Frankfurt-Main erfolgten Sektionen finden konnte. Eine statistische Auswertung der Gesamttodesursachen war bereits früher erfolgt (1942).

In einer umfangreichen Monographic « Familienuntersuchungen bei missbildeten Totgeborenen und Frühverstorbenen » sollten die im folgenden zu besprechenden Befunde zusammen mit anderen letalen Missbildungen (Herzmissbildungen, letalen Hernien, Ektopien, Missbildungen des Magen-Darmkanals, der Haut und der blutbildenden Organe sowie auch Mongolismus) Anfang 1945 als Ergänzungsband der Zeitschrift für menschliche Vererbungs- und Konstitutionslehre erscheinen. Leider ist die bereits ausgedruckte, fertige Arbeit am Ende des letzten Krieges der Zerstörung von Würzburg zum Opfer gefallen. Bei den gegenwärtig beschränkten Druckmöglichkeiten in Deutschland habe ich unter dem Titel « Frühletale Missbildungen und Hereditat » bisher lediglich ein kurzes Referat der Arbeit geben konnen. Für das grosszügige Angebot von Herrn Prof. Dr. L. Gedda, einen Teil der Arbeit in die Acta geneticae medicae et gemellologiae aufzunehmen, möchte ich deshalb meinen ganz besonderen Dank aussprechen.