Pedagogical Anthropology, Maria Montessori [online e book reader TXT] 📗

that while the original progenitors had angular seed and green cotyledons, and round seed and yellow cotyledons, certain hybrid plants inherited the round seed of the one and the green colour of the other; or the angular seed of the one and the yellow colour of the other. In the same way, it may happen, for example, that the colour of one plant may combine with the height of another, etc. That is, that each separate characteristic of the progenitor is independent and may combine with the characteristics of the other progenitor—even to the point of separating the colour from the form, as in the case cited.

What we find in hybrids, then, is not a separation into two types of generative cells, considered as united and complex entities; but every separate germ cell may break up into as many different potentialities as there are separate characteristics in the individual; and that, too, not only as regards the separate minute parts of the individual body, but, within the same organ, as regards the shape, colour, character of the surface, etc.

Such phenomena of Mendelism cannot as yet be generalised; yet it has already been established by a host of experiments that a great number of characteristics obey the laws of Mendel, such, for example, as the character of the hair or plumage; the gradations of colour, the abundance or absence of hair; physical malformations, such as cerebral hernia in poultry; the character of locomotion, as in the jumping mice: and even normal physiological attributes connected with the epoch of maturity in certain plants.

But the manner in which the dominant character asserts itself is not always uniform. There are times when a fusion of antagonistic characters takes place. Thus, for example, when two varieties of the mirabilis jalapa are crossed, one having red flowers and the other white, a fusion of the colours takes place in the first generation, and all the plants have pink flowers. In the second generation we get, for every plant with red flowers, two with pink flowers and one with white. That is, the law of disjunction has again asserted itself, but the individual hybrids merge their antagonistic attributes, which remain, nevertheless (as their differentiation proves), separate one from the other in the sexual cells.

Another phenomenon observed in individual hybrids is the intermingling of characteristics. For instance, there are cases where the flowers of a hybrid produced by a plant with red flowers and another with white are variegated with red and white stripes.

Accordingly, the transmission of antagonistic attributes through the individual may be divided into three different methods:

Transmission Exclusive. By fusion. By intermingling.

In the first case, the character of one of the parents is transmitted intact; in the second, the formation of a new characteristic results, constituting a form more or less nearly midway between those from which it comes and whose fusion it represents; in the third case (which is very rare and seems to obey Mendel's laws in quite an uncertain way), the result is a mosaic of the fundamental attributes.

Of special interest to us are the two first methods of hereditary transmission of characteristics. Even before Mendel's discoveries, anthropologists had observed that in the intermixture of races certain human attributes remained distinct while others merged. In the first case they called the individuals hybrids, and in the second case they called them metics. Take, for example, the colour of the skin when black and white merge in the so-called mulatto.

Other characteristics, instead of merging, intermingle, as for instance those that are internal or related to the skeleton, and those that are external or related to the soft tissues and the skin. It may happen, for example, that where one race has an elongated head and black hair and another has a round head and blond hair, the result of their union will be hybrids with elongated heads and blond hair or vice versa. Similarly, if one of the parents is tall of stature and fair complexioned, and the other of short stature with a dark skin, these characteristics may be interchanged in the hybrids. A very common occurrence, as regards the colour of the hair, is the fusion of blond and brunette into chestnut; while parents with chestnut hair may have either fair-haired or dark-haired children. In his book entitled Human Races and Varieties, Sergi says in regard to hybridism: "It is impossible to ignore human hybridism, which, for that matter, has been demonstrated under various forms by all the anthropologists; America, in itself alone, offers us a true example of experimental anthropology in regard to this phenomenon. Already the result of investigations shows that human hybridism is multiform among all the peoples of the earth; but what is best known of all is the exchange of external characteristics and their intermingling with the internal; that is, the combination of external characteristics of one type with internal characteristics of another type. It is easy, for instance, to find cases in which a certain colour of skin and hair, with the special qualities proper to them, are found combined with peculiarities of the skeleton that do not rightfully belong to types of that particular colouring, and vice versa; and this same phenomenon may be observed regarding certain separate attributes, and not all of them—such as the stature, or the face with its outer covering of soft tissues, or the shape of the skull alone.

"If we observe our European populations, that call themselves a white-skinned race, but whose whiteness has many different gradations, we are convinced of the great intermixture of characters, and, what is more, a varied mixture resulting in a great variety of individual types, consisting of characters differing widely from one another. It requires a very accurate and very minute analysis to distinguish the different elements that are found in the composition of ethnic characters in individuals and peoples. Undoubtedly these intermixtures and combinations of character differ in their constituent elements and in the number of such elements in the different nations, according to whether we study those of the south, or the centre, or the north of Europe; and this results from different degrees of association with mongrel races.

"But a more important fact, and one that seems to have escaped the attention of anthropologists, is the absence of fusion of internal and external characteristics in the product of such intermixture. We find only a positional relationship between the different ethnic elements, a syncretism or superposition of characteristics, and a consequent readiness to disunite and form other unions. This phenomenon has already been demonstrated in America, on a mass of evidence; but it is apparent also in Europe, among the peoples that are seemingly most homogeneous, if by careful observation we separate the characteristics that constitute the ethnic types; and not only the types, but the individuals belonging to the different peoples."

And in the following passage, Sergi expresses himself still more clearly:

"From my many observations, it follows, further, that human hybridism, or meticism, as others choose to call it, is a syncretism of distinct characteristics of great variety, and that these do not modify the skeletal structure or the internal characteristics, excepting by way of individual variation; it may happen that separate parts of the skeleton itself acquire characteristics peculiar to themselves. The stature, the chest formation, the proportion of the limbs, may all be in perfect correlation and be united with external characteristics of diverse forms, as for instance with different forms of cranium, or the cranium may be associated with different facial forms, and conversely. Furthermore, the forms adapted separately and in part in hybrid composition remain unvaried in their typical formation. The face retains its typical characteristics in spite of its union with different forms of cranium; and similarly the cranium preserves its architectural structure when combined with different types of face. The stature maintains its proportions in spite of combinations with diverse cranial and facial types, and in spite of varied colours of skin and hair."

The foregoing page, that I have borrowed from this masterly investigator, is most eloquent testimony that, in regard to the phenomena of hybridism, man also comes within the scope of Mendel's laws. There is something wonderful in the power of observation and intuition shown by Sergi, who, running counter to the convictions of the majority of anthropologists, arrived through these conclusions at a truth the key to which was destined to be discovered later on through studies, very far removed from anthropology, such as were pursued by the botanists Mendel and De Vries. While Mendel was led by his experiments to the discovery of the laws based upon his ingenious hypothesis, Sergi was drawn simply by observation to conclusions that to-day are confirmed by experience. And from difficult observations of single characteristics taken separately, Sergi demonstrated, in his ingenious studies, their persistence through innumerable generations; while, through the identification of separate characteristics, he achieved that brilliant analysis of the races which revealed to his anthropological insight that the European varieties of man originated among the peoples of Africa and Asia. Unquestionably, the laws of Mendel confirm what hitherto were considered, in the scientific world of Europe, simply as the individual hypotheses of Sergi, but which American anthropologists recognise and welcome as a scientific truth, brilliantly observed and expounded by the Italian anthropologist.

Thus, through single characteristics, through particularities, we may read the origins of races; and recognise which are the constant characteristics and which the transitory ones.

Accordingly, let us keep these principles in mind, as we proceed further in our investigation of the phenomena of heredity.

Mendel's laws, however much they may be discredited or illuminated by further experience, serve in the meanwhile to give an absolutely new conception of the individual and to shed light upon many obscure problems relating to heredity.

The individual is the product of a combination of germ potentialities, which, in the case of hybrids (and consequently always in the case of man, who is the product of racial intermixture), meet in accordance with the mathematical laws of probability. One might almost conceive of a formula, or, better yet, a calculation, in accordance with which the individual resulting from any given germs might be predetermined; if it were not for the fact that the calculations would become infinitely complicated through the multiplication of characteristics. With only ten pairs of characteristics it is already possible to form upward of 1024 kinds of germinal cells and these give rise to 1,000,000 different combinations.

Furthermore, through the law of dominant characteristics, the combinations of germs would produce in the descendants 1000 varieties distinguishable by their external appearance, and 60,000 differing only internally, that is, in their germinal cells.

There remains, however, one general principle: the individual contains not only his personal attributes, but also other attributes which belonged to his ancestors, and which are latent in him, and may reappear in his descendants. Consequently, if the individual is a hybrid, he must be interpreted not only through himself alone, but through the history of his family; and the characteristics which he may transmit are not those of his own body, but those of his origin.

The individual body is nothing more than a "temporary expression" of those germinal characteristics which have united to give it consistency; but the complex transmission of characteristics rests wholly with the germinal cells. The problem of heredity is transferred from the individual and from the series of individuals, who are simple and transitory products of combinations, to the sexual cells and their potentialities. And this is unquestionably an absolutely new scientific concept, and a revolutionary one as well, capable of drawing in its wake a lengthy evolution of thought. Since the germinal potentialities determine the single characteristics, they may be considered as the atoms of the biologist. "The field of investigation," says Bateson, "does not appear to differ greatly from that which was opened to the