This opinion was strengthened by the fact, that no case occurring in New Jersey could be traced to a Massachusetts origin, in which State it was claimed that the disease never had existed in this country previous to its introduction there. It was, therefore, denied by the veterinary surgeons in the Eastern States, that the disease in New Jersey was the true European pleuro-pneumonia, but it was called by them the swill-milk disease of New York City, and it was assigned an origin in the distillery cow-houses in Brooklyn and Williamsburg. In 1860 it found its way across the Delaware River into Philadelphia, spreading very rapidly in all directions, particularly in the southern section of the county, known as The Neck,--many of the dairymen losing from one third to one half of their herds by its devastating influence. In order to save themselves--in part, at least--from this heavy loss, many of them, upon the first indications of the malady, sent their animals to the butcher, to be slaughtered for beef. In 1861 the disease found its way into Delaware, where its ravages were severely felt. So soon, however, as it became known that the disease was infectious or contagious, an effort was made to trace it to its starting-point; but, in consequence of the unwillingness of dairymen to communicate the fact that their herds were affected with pleuro-pneumonia, all efforts proved fruitless. In 1860 the disease found its way up the Delaware to Riverton, a short distance above the city of Philadelphia. A cattle-dealer, named Ward, turned some cattle into a lot, adjoining which several others were grazing. The residents of this place are chiefly the families of gentlemen doing business in the city, many of whom lost their favorite animals from this destructive malady. The first case occurring at this place, to which the author's attention was called, was a cow belonging to Mr. D. Parrish, which had been exposed by coming in contact with Ward's cattle, had sickened, and died. An anxiety having been manifested to ascertain the cause of the death, the author made an examination of the animal, which, upon dissection, proved the disease to be a genuine case of the so-called pleuro-pneumonia. This examination was made August 20th, 1860, at the time of the Massachusetts excitement. Two cows, belonging to Mr. Rose, of the same place, had been exposed, and both had taken the disease. His attention having been called to them, he placed them under the author's treatment, and by the use of diffusible stimulants and tonics, one of these animals recovered, while the other was slaughtered for an examination, which revealed all the morbid conditions so characteristic of this disease.