He spent two years at the Hôpital de la Pitié in Paris working alongside J. Darier, a leading light in European dermatology and in the laboratory of the Saint-Louis hospital run by Gastou, who was in touch with the latest theories in anatomopathology. He returned to Barcelona after two years and alternated between work in private medicine and hospitals. First he worked in the Poor Children's Hospital of Barcelona for two years, and intermittently at the Hospital de Santa Creu in Barcelona. Naturally he was working in the Dermatology services of both these centres. He continued to work in this field until his untimely death on 9 May 1922. He was not yet 43 years old, and still in his intellectual prime.

In addition to his hospital activity, which brought him considerable prestige over the years, he also took part in public events. However, as a doctor, he did appear at a number of clinical events and sessions, sometimes as a spectator and other times in a more active capacity, although he focused mostly on writing scientific articles. He produced some forty such articles, half a dozen in French, and various others that he never published, of which unfortunately all but five have been lost. As far as his public life was concerned, he spoke out strongly against the political tyranny in his native town in 1909, an indication of his independent–mindedness and spirited nature. This was probably one trait that did not help him in his aspirations to occupy public posts, much less to be rewarded with academic merits.

Historically, his legacy in terms of scientific contributions can be divided into three main areas. Firstly, he introduced new dermatological methods and theories, primarily from the French School, during a vital period in which Spain was struggling to come out of a period of scientific stagnation. Secondly, he made original contributions both in the field of dermatology and in its extension in terms of syphilography. Finally, he revised a whole series of topical issues.

The period he spent in Paris increasing his knowledge and speciality allowed him to introduce, or rather to consolidate and demonstrate, the clinical advances on the basis of anatomopathology, bearing in mind the advantage of having been in direct and sometimes personal contact with the most outstanding figures of the French School with which he always stayed in touch through the Societé Française de Dermatologie et de Syphilographie with masters such as L.A. Broca, J.A. Fournier and others less well-known figures.

As far as his original contributions are concerned, we could point to the studies he made on fungoid mycosis, which he identified as a lymphomatoid process. This finding, which was important in itself, also served as the basis for modern biochemical, ultrastructural and immunological studies aiming to decipher the workings of malignant, originally extramedullar proliferations of the lymphoid system. On a scientifically less well-known level, he studied the principles and differences of skin pathology in pediatrics and finally produced a brilliant series of statistical studies on the effects and results of arsenical therapies on syphilis by active lumbosacral administration, particularly for the treatment of Syphilitic Myelopathy and general Paresis.

These revisions focused on Syphilis, which in the early twentieth century represented a complex pathological framework with enormous repercussions for society. On this issue, he published a "Retrospective Diagnosis of Syphilis", which was the treatise on all the syphilitic stigmas, the lesions that they caused and the way to apply differential diagnosis. Naturally, the advent of antibiotics caused a sea change in the way that syphilis was dealt with. However, at the time, this work was to become a fundamental guide in bringing to light the existence of an age-old syphilis, which from its outset represented an unpredictable source of contagion. Finally, he revised the concept of Parasyphilis, which remained valid until the nineteen-forties, establishing that it covered a series of luetic processes, in other words caused directly by Treponema and defined by their common sclerotic nature.

The contribution made by Umbert lies in introducing and consolidating a scientific awareness of common dermatology, a process that took place in the first two decades of the last century. The absence of studies in this chapter of the history of medicine and the changes that occurred in the mid-twentieth century overshadowed this work which is only now coming to be recognised for the great contribution it made to the field, and it is highly likely that subsequent studies will help to bolster its importance within local scientific culture.