During his research work, he examined a stool sample from two young Mayagϋezan patients and found very different eggs. His interest led him to follow the clinical course of the patient and when they died, he performed an autopsy and found the eggs of the "Bilharzia" in the vessels of the intestine, with changes in the liver, as it is known in Puerto Rico. Bilharzia, later defined as Bilharziosis, was discovered in Europe by Theodor Ma ximilian Bilharz, who gave the genus its name. This disease is epidemic in Africa and was probably introduced in the island in the times of slavery with the blacks coming from Angola, Congo and Cafrería. In the medical report made by Dr. Isaac Gonzalez Martinez to the Medical Association of Puerto Rico, was the first description of the disease "intestinal Bilharziosis" in America, whose publication toured all medical libraries and researchers around the world. He was appointed as Special Commissioner for the clinical and bacteriological diagnosis of some cases of leprosy in Aguadilla and an epidemic of typhoid fever in Mayagϋez. In Arecibo he discovered the first case of a new species of "Distomatosis Hepatica" in a peasant.