A practical manual for dissection, showing how to carry out an anatomy from the first incision onwards. Massa based his work on his experience gained from numerous dissections that he had undertaken in the hospital of SS. Petro et Paolo in the monastery of SS. Giovanni e Paolo. In the full title of the book Masso
"promised to reveal parts, functions, and uses of the body overlooked by others, ancient and modern. In his biography of Vesalius, C. D. O'Malley found the book 'somewhat overated, making certain contributions and correcting some errors, but remaining too much under the shadow of Galen.' Later he gave a more favourable appreciation, noting Massa's introduction of the term panniculous carnosis and praising other aspects of his work - his account of the abdominal wall, intestinal canal, and appendix, his observation that the size of spleen varied in those suffering from certain ailments, the discovery of the prostate gland, his denial of the seven-celled uterus, his reference to the malleus and incus, and his statement that interventricular septum was a 'dense and hard substance without a cavity', perhaps a denial of Galen's interventircular pores and a hint towards the pulmonary circulation of the blood. At the same time, O'Malley commented unfavourably on the 'cryptic brevity' of so many of Massa's descriptions. This is a justifiable comment, but Massa's brevity was perhaps inevitable in what was, after all, a short book on how to perform an anatomy, not an account of the fabric of the body in the manner of Vesalius....For Massa, anatomy remained an adjunct to medicine. It was the groundwork for surgery, showing the correct sites for incisions and areas where especial care was needed. He noted the extreme consequences of surgical mistakes; ignorance of anatomy could cause the death of patients. it is no surprise that he digressed into surgery, dealing amongst other things, with wounds of the peritoneum and demonstrating his own method of sewing up intestines. Anatomy was also the guide to morbific processes, and many of his patients ended their courses of treatment on his anatomy table, sometimes at the request of relatives.
"The Liber introductorius is best judged in its own terms as a practical manual. It is full of hints such as the use of probes to examine cavities, and pipes, syringes, and bellows to flate organs such as the bladder, kidneys, stomach, and somb to show their capacity and explore their function. it also contains useful suggestions such as boiling the liver as a preliminary to studying its veins. The treatise amply justifies L. R. Lind's assessemtn of it as a 'remarkably clear account of the human body by a skilled dissector who was proud of his ability" (Richard Palmer, "Nicolò Massa, his family and his fortune," Med. Hist., 25 (1981) 385-410).
"It is clearly evident, that Massa anticipated the modern anatomists, describing the presence of fluid intracranially. [Massa's Chapter XXXVIII on page 84]. Because this work was original, the evidence accurate and based on autopsy observations and what is more other scientists cited his work, thus we have to recognize Massa's scientific priority for this discovery.8-9' This great anatomical discovery is widely recognized as a milestone in the development of neuroanatomy and neurophysiology" (Leszek Herbowski, "Massa versus Haller: Priority of the Cerebrospinal Fluid Discovery," Neurol. Med. Chir. (Tokyo), 58 (2018), 225-227).
Full text translated into English by L. R. Lind, Studies in pre-Vesalian anatomy...(1975).