Mascagni was born in the small village of Castelleto in central Italy in February of 1752. Castelleto is near Siena in the province of Tuscany some 120 miles north of Rome. Mascagni received his early education at home and then was sent to the University of Siena where he studied philosophy, literature, physics, mathematics, and medicine.

His scholarship, intelligence, and interest in the natural sciences were soon noticed by Pietro Tabarrani, professor of anatomy at the university. Tabarrani became his mentor, and Mascagni was appointed prosector in anatomy at the university after receiving his medical degree in 1771. Tabarrani's health began to fail, and when he was forced to retire in 1774 because of blindness, Mascagni succeeded him as professor of anatomy. Mascagni felt so strongly that his professorial responsibilities lay in teaching and in advancing anatomical knowledge that he decided not to work in clinical medicine preferring to devote himself entirely to teaching and research.

When Mascagni became prosector at Siena in 1771, Tabarrani suggested that he concentrate his investigative efforts on the lymphatic system. In making this recommendation Tabarrani showed a great deal of foresight, and it was Mascagni's research in this area that was to bring him lasting fame and recognition. Gaspare Aselli (1581-1626) had made the first true description of the lymphatic vascular apparatus in 1627 and later, in the eighteenth century, when Frederik Ruysch (1638-1731) had tried to stimulate interest in the lymphatic system in Holland, the rest of Europe paid him little attention. This may have been because of the influence of Albrecht von Haller (1708-1777), who had cast doubt on the entire lymphatic system by refuting the existence of lymphatic vessels in several parts of the body. The French scientific community was also concerned about research in this area and in 1784 the Academy of Sciences of Paris offered a prize for the best work demonstrating the lymphatic vessels. Mascagni submitted two substantial illustrated reports to the Parisian Academy. Unfortunately, however, his work reached Paris after the deadline for acceptance of entries; but nevertheless, members of the Academy were so impressed that they awarded Mascagni a special prize. Since much of his work dated back eight to ten years,he decided to publish his work in French and Italian that same year in order to protect the priority of his discoveries.

Mascagni continued his studies of the lymphatic system, and in 1787 published a large folio volume entitled Vasorum lymphaticorum corporis humani historia et iconographia. This important monograph contained the first systematic and definitive description of the human lymphatic system. A large folio, it contains forty-one brilliantly executed copperplates which faithfully represent the details of the lymphatic system. Mascagni has been credited with discovering some 50% of the lymphatic vessels, and it was this work that opened the way for continued progress in our understanding of the anatomy and physiology of the human body.

In achieving such significant and accurate results, Mascagni performed numerous experiments, examined and repeated the observations of other investigators, and developed totally new methods or revised the techniques of other scientists in order to meet the needs of his research. We must remember that he was without the benefits of modern technology; yet he reached such a degree of perfection that modern researchers find it extremely difficult to duplicate his work. He used mercury as the contrast medium which he injected into the body's peripheral lymphatic networks by using a simple glass tube bent at a ninety degree angle at one end and tapered to an extremely fine point. Mercury was poured into the other end of the glass tube and it quickly flowed through whatever part of the lymphatic system was under study. By following the mercury injection with careful dissection, Mascagni obtained magnificent preparations which can still be seen and admired in the museum of the Institute of Normal Human Anatomy at the University of Siena.

Mascagni disapproved the theory that the lymphatics originated from the terminal arteries and were continued in the veins through various very fine tubules. This ended the idea that there were arterial and venous lymphatics. After thoroughly examining the work of other anatomists and analyzing the results of his own investigations, he concluded that the lymphatic system originates from all the internal and external cavities and surfaces of the body and is directly related to the function of absorption. By means of colored injections he demonstrated that there is a link between the lymph and serous vessels. He also refuted the belief that there was an anastomosis between the lymphatics and the veins by showing that there is no connection between the two systems except at the point where the thoracic duct and the thoracic vein merge into the venous system. Mascagni discovered and described lymphatic vessels in regions of the body where they had not previously been known to exist. He determined that all the lymphatics pass through one or more lymph nodes during their course and provided excellent illustrations to document this fact. He did not limit himself to the study of the anatomy of the lymphatic system alone but also studied its physiology and pathology and emphasized the vital role it plays in maintaining the body's well being.

After Mascagni's death in 1815, manuscripts and sketches for three additional works were found among his papers. The first, an anatomy for artists, was edited and published by two relatives at Florence in 1816. The relatives died soon after its publication, and a group of individuals interested in the welfare of Mascagni's family undertook the publication of the other two works. Responsibility for editing these last two works was given to Francesco Antommarchi (1780-1838), a physician who had been Mascagni's prosector. The second work, dealing with histological investigations into the anatomy of the human body as well as animals and plants was published in two editions, one at Florence in 1819 and the other at Milan in 1821.

The story of Antommarchi's involvement with the third work is an interesting and involved tale. However, suffice it to say, that difficulties arose which ultimately led to his publication of a pirated edition. The authorized work was assembled and edited by three professors from the faculty of the University of Pisa.

The Anatomia universa is a comprehensive work of anatomy lacking only microscopic anatomy, histology, and the lymphatics of the skin. The beautifully executed plates depict the anatomical and skeletal structure of the human body in great detail. In addition, Mascagni included a series of plates that cover the abdominal organs, gravid uterus, placenta, and fetus.

The book was published in a series of nine parts between 1823 and 1832 at Pisa. Each of the 44 plates in the University of Iowa copy is hand-colored and accompanied by a duplicate outline plate which contains nomenclature for identifying the anatomical parts in the accompanying volume of text. The plates are so large that it has never been bound and is stored in a large book-shaped wooden box especially constructed for that purpose. The plates are so designed that a man five and one-half feet tall can be assembled from three of the plates if they are joined together. The plates were superbly engraved and the hand-coloring by pen and brush was done so carefully and with such skill that the artist often achieved a three-dimensional effect.

Mascagni also made a number of significant contributions to science in other fields but he will always be remembered for this work on the lymphatic system. Indeed, he is best known for his Vasorum lymphaticorum, but that work is overshadowed, as a work of art, by his Anatomia universa, and it is ironic that this great work should be so relatively unknown. Its great cost and its rarity have undoubtedly contributed to its undeserved obscurity. In fact, the University of Iowa's copy appears to be one of only three or four copies in the United States.