As it is well known, connective tissue is not only having a role into the metabolic exchange, defense and reactional process but is particularly important as a support of all human system. Therefore, next to the inflammatory pathology of connective tissue (mesenchymitis or collagen diseases) must be taken under consideration a non-inflammatory pathology, wich is mainly consistent in a primitive change of its structure, related to its supporting capacity.

The Authors name such a condition as Mesenchymosis (as proposed by Lunedei for these degenerative changes of connective tissue). After a syntetic review of the historical evolution of concept of « connective lability », the AA. report the results of a series of researches, carried out with the purpose of establishing the eventual association of some clinical pictures as Arthrosis, Varicous veins, Hernia and aspects of Venular fragility (epistaxis juvenilis recidivans, spontaneous ecchymosis) wich are due fundamentally to a reduced supporting capacity of the tissues of mesenchymal origin.

An individual association of these conditions as well as familiar were considered.

The interview of 600 persons with at least one of these morbid conditions, under study, and of 600 controls, showes that Arthrosis, Hernia, Varicous veins and the condition of Venular fragility are, in the majority of cases, actually or in the history, variously combined. Such a combination, as compared to the controls, is statistically significant.

The familiar interview was carried out on the families of 166 probands with some condition of connective lability and on 100 families as controls. It showed that the family members of probands with one of above-mentioned conditions, have, in hig percentuage, statistically significant when compared to the controls, the same morbid condition, and that a predisposition to all group of condition really exists.

Therefore we must admit not only a predisposition to a single disease but to all the group of diseases.

Furthermore a genetic inquiry was carried out, according with the Lenz-Hogben method, based on the hypothesis that the group of conditions above-mentioned (Arthrosis, Hernia, Varicous veins, Venular fragility) may be transmitted as a single hereditary factor.

This genetic hypothetical factor is transmitted as dominant autosomal charachter, with reduced penetrancy, varying from 77% to 97% (being lower when the parents are phenotypically healthy, higer when one or both of them are affected).

Because the hereditary character, for the predisposition particularly strong, and for the number of the morbid manifestations it seems possible to name diathesis (mesenchymosic diathesis or mesenchymosis) the predisposition to such a syndromic group.

It is possible that changes in biochemical state of connective tissue and in the ground substance and collagen fibers ratio may play an important role in the pathogenic mechanism. With the genetic factor other situations have therefore a particular interest; first in this group are the endocrines ones, which effect variously the unset of different conditions, due to the genetic factor itself.

The Authors underline, once more, that this syndromic group (in which inflammation, when present, acts as a secondary, not obligatory, complication) is to be kept distinctly separed, even from the hereditary point of view, from the other large group of diseases of connective tissue i. e. the so-called reactive mesenchymopathic diseases or mesenchymitis (not properly called collagen diseases or collagenosis and by some even mesenchymosis). That are definitively different, because the inflammatory nature, from the mesenchymosis diathesis (or heredoconstitutional mesenchymosis) which are due to changes of the supporting function of the tissues of mesenchymal origin.

A case is described of uncommon vertebral malformation simulating a duplication of the spine. Pathogenesis, etiology and terminology of such an anomaly are briefly discussed.

Report of 44 cases of rheumatic heart disease with genetics observations of transmittance of rheumatic fever and cardiovascular diseases and discussion about the relation betwen the two diseases.

Le attuali conoscenze sulla fisiopatologia dei connettivi ci permettono di considerare questi tessuti sopratutto per la loro attiva partecipazione agli scambi metabobolici e, in condizioni patologiche, per le loro funzioni difensive ed in genere reattive. È venuto a crearsi un grande raggruppamento nosologico — le mesenchimopatie reattive (impropriamente dette malattie del collageno) — la cui base istopatologica e patogenetica consiste in una particolare alterazione del connettivo, particolarmente della sostanza fondamentale di questo.

La riconosciuta essenziale importanza di questo tessuto nello svolgersi dei processi flogistici ed istoreattivi in genere non deve tuttavia far dimenticare l'altro aspetto della funzione del connettivo da più tempo noto, quello della sua funzione di sostegno, da intendersi non solamente in senso meccanico passivo, ma quale partecipazione attiva alla regolazione ed alla eufunzionalità dei vari tessuti, organi ed apparati.

Una primitiva turba della funzione meccanica di sostegno del connettivo può essere responsabile di molteplici quadri morbosi e soprattutto può costituire quella patologia di sfondo capace di creare, più spesso condizionare e modificare una eventuale patologia di primo piano.

Accanto ad una patologia del connettivo schiettamente flogistica (le mesenchimopatie reattive) deve essere considerata pertanto una patologia dei tessuti di origine mesenchimale a impronta non flogistica (nella quale i fenomeni flogistici, se presenti, costituiscono una contaminazione secondaria non obbligata) il cui momento patogenetico essenziale risiede in una primitiva alterazione della funzione di sostegno, che, pur nella più ampia visione attuale delle funzioni dei connettivi, rimane sempre fondamentale.

Two errors in an earlier paper are corrected. The general conclusions arrived at originally remain unchanged.