The A. reports some fundamental biological proceedings in a preventive treatment of hereditary diseases.

She divides prophylaxis in idiotypic and phenotypic and after having examined the different aspects of the problem, concludes that a positive eugenetica is possible by acting on environment disposing or exposing conditions. The A. finally indicates how studies should be carried on in order to attain this object.

Though conception and reproduction have been favorite topics of the biologists of all ages many of the simplest facts of generation are still lacking their proper explanation. They remained mysteries and stimulated wild speculations not only among the uneducated people but also among the physicians, naturalists and others engaged in the scrutiny of Nature.

We describe a fortuitous observation on two rats united in parabiosis since nearly a year.

One of the two, belonging to an oncoreceptive race, fell sick of a round cell sarcoma, of extremely malignant nature, which spread itself through various metastases to all the organism, invading especially the lungs and causing tha animal’s death.

The other, of oncorefractory race, did not fall sick, although he was united to the first by abundant vascular and lymphatic communications, and that the common abdominal cavity was full of an hemorrhagic exsudation containing numberless cells coming from the tumorous decomposition. As the question is of a parabiosis of long duration and of a natural tumor of great malignity, the observation, better than the preceding ones on grafted tumors, favours the demonstration of the importance of the individual constitution of a subject sick or not of cancer.

Under the name of “Progenesis” (from the prefix “pro “, in front, and of the Greek “genesis “, generation) a new conception and classification of the factors of development were proposed by R. Turpin, the progenesis grouping “the whole of the hereditary and non hereditary factors that preexist to the fecundation and that concur to the formation of the being and to its development”.

This conception has the advantage of designating indifferently, to all progenitic factor, hereditary as well as non hereditary, a place marked in advance; it has the advantage of showing beside the paternal maternal factors, the characteristic progenetical factors of the couple; it has the advantage to draw the attention on factors which were before neglected (age of mother, age of father, rank of birth, sex of the preceding pregnancy, interval between pregnancies, number of pregnancies, etc.) and whose importance increases in proportion as the gathering of the facts is abundant enough to lend itself to the statistical analyses; it has lastly the advantage of leading to an etiological prevention of the congenital defects, trying to draw the most advantage from the surrounding factors, without discarding, when they are imposed by the circumstances, the possibilities brought to their right proportion of the eugenic selection.

To illustrate this progenesic conception of the ontogenesis a simple example, the gemellity, deserves to be retained.

If we consider the gemellity as a deviation in regard to the simple pregnancies, it constitutes at the same time the more frequent and the best registered of anomalies. It lends itself to the study of its relations with divers progenesic factors which the authors regard by turns with the complement of their personal researches : age of the progenitors, rank of the pregnancy, sex of the product of the anterior last conception.

If on the other hand, we consider the gemellity itself as a progenesic factor, we can study on the development, and for instance, which the authors have done, on the rate of masculinity. This study has lead them to put in value the phenomenon of diminution of the masculinity in relation to the degree of the multiplicity of pregnancy.

An old problem of gemellary research lies in the determining cause of gemellogenesis. Two new observations of the family order, in agreement with other similar results, are further evidence in favour of the opinion that in the origin of twins a certain part can be played by some hereditary property of the paternal side.

Gemellary research is the best method to establish the respective importance of heredity and environement in the developement of man. A new problem of gemellary research has arisen owing to the fact that MZ twins can differ in some illness, without the common causal analysis heredity-environement being able to give a satisfactory explanation. For example in the case of cancer it is demonstrated that the “autonomous” genesis of an illness must be taken into account i. e. without an appropriate hereditary cause or without an esogenous cause visible for all. Such an “autonomous” genesis of an illness has become undestandable only on the basis of microphysical knowledge.

From the genealogico-statistic inquiry made on a group of 252 leukemics hospitalised in Lombardy during the years 1945-1950, and from the comparison made on an adequate material of control; the Authors have come to the conclusion that for the realisation of the leukemia the idiotypic composition has less value than that of the surroundings. They have over more noticed a greater incidence of neoplasiae in the familiars of the acute leukemics and cronic myeloids in regard to the controls.