TYPE. - By "type" or "typical phenomenon" is meant that which, given a collectivity of phenomena that within certain limits differ from one another, is best able to represent the entire collectivity. Statisticians consider as "typical" the character that corresponds, in the seriation, to the most numerous class, to the most common variant among many rarer ones, sometimes even the simple resultant of a large number of observations. By "habit" or "morphological type" is meant the particular bodily architecture of an individual, detectable through the correlation of anthropometric measurements of the segments and cavities of his body.
A true typological science is of very recent origin, having its founder in Achille De Giovanni (1838-1916), yet a tendency to classify individuals according to various groups is extremely ancient, so much so that Hippocrates already distinguished two pathological human types: the long (with limbs long relative to the trunk, thin, predisposed to phthisis), and the short (predisposed to apoplexy). Until 1800, however, the classification of individuals most in use was that proposed by Galen and championed by the Salernitan school, which was less a morphological classification than a temperamental one, inasmuch as it was based on the clinical and functional characters determined by the presence or absence of four presumed substances (humors) in the organism: blood, bile, phlegm and black bile. From this came four human types or temperaments: the sanguine, the choleric or bilious, the atrabilious or melancholic, the phlegmatic.
A. De Giovanni, by contrast, brought the study of human individuals onto a new plane, adding to pure clinical observation a study based on rigorous measurements of the human body, thus initiating an anthropometric study of the constitution (v.) of individuals, that is, of their bodily build, a value understood both in an absolute sense and in the reciprocal relations of the individual parts of the body to one another. He thus created his three "combinations" (or habits), not only identifying three distinct types according to external morphological appearance, but also assessing from the external constitution the development of the internal organs, their functionality and their morbid dispositions. De Giovanni recognized brachytypes, longitypes, and normotypes. Contemporaneously with his studies, numerous other researchers occupied themselves with this new branch of medicine, in Italy and throughout the world, proposing more or less similar classifications. Noteworthy are: Kretschmer, Stiller and Kraus in Germany, Naegeli and Jung in Switzerland, Marañon in Spain, Obermer and Cavadias in England, Marinescu in Romania, Charcow and Nicolaeff in Russia, Biant and Stockardt in North America, Rossi, Boccia and Berardinelli in Latin America.
Anthropometry took a decisive step forward through the work of G. Viola, who was the first to have the idea of applying to medicine the law of errors (binomial law or law of probabilities) of Quetelet-Gauss, for the evaluation of the frequency of a given character in a given collectivity of individuals. In this manner, one can graphically obtain a binomial curve whose apex represents the "norm" in the statistical sense, while on the two branches (the ascending and the descending), the variations from the norm are arranged. Viola thus proposed the calculation for establishing the magnitude of the quantitative deviation from the statistical norm and the index of severity of the deviation. On the basis of his studies he formulated a new classification, based both on simple measurements of the trunk and on the value of the trunk-limbs ratio, considering of the two terms the first as an expression of vegetative life, the second as an expression of relational life. Thus for Viola there exist macrosplanchnic, normosplanchnic and microsplanchnic types according to the dimensions of the trunk, while in relation to the varying proportion of trunk to limbs there are brachytypes (trunk further removed from the "norm" than the limbs) and longitypes (limbs further removed from the norm than the trunk), while if the two deviations from the norm are equal, both for the trunk and for the limbs, one has the normotypes. In this way the types, or rather the "constitutional ectypes," are the product of a single universal biological law of deformation of the mean type, a law enunciated and demonstrated by Viola in 1907: "The more an organism accelerates its development, the more it differentiates itself morphologically.
but all the less does it acquire somatic mass, and inversely" (law of morphological-ponderal antagonism).
N. Pende subsequently introduced new modifications and refinements to the anthropometric method, replacing the statistical norms then in force with particular statistical norms for each racial entity. It is also due to Pende to have simplified the anthropometric study of individuals by measuring the relationships existing among three simple measurements: height, mean thoracic perimeter and weight. The height-weight ratio is an index of the relative weight of the body, making it possible to divide individuals into hypersomic, hyposomic and normosomic; while the height-mean thoracic perimeter ratio gives the value of the body's mass development, whereby there will be normolineal, brevilineal and longilineal individuals.
The simple typological and constitutional study of individuals has, however, been increasingly refined and completed in recent times, so that at present typology has been replaced by "biotypology" (v.), that is, by the complete study of the individual from the somatic, functional or endocrine and neuropsychic point of view.
Bibliography7 works
Alessandro Marolla