Page:The growth of medicine from the earliest times to about 1800.djvu/140

 the following terms: "This practice is not only cruel, but useless, and at the same time it derogates from the dignity of the healing art, which is intended to be a blessing and not a source of pain to man; for those in whom the abdominal cavity is first opened and then the diaphragm divided, die before it is possible to make the scientific examination 'during life' which constitutes, as it is claimed, the justification for the entire procedure." (Puschmann.)

As regards the work done by Erasistratus in the departments of anatomy and physiology, the following statement may be made: He threw a great deal of additional light upon the structure of the lacteals, the valves of the heart, the brain, the nerves, and several other portions of the body; and he assigned to the pneuma, or breath,—of which he assumed that two kinds exist,—the most important rôle in the mechanism of life. According to the description given by Galen and reported by Le Clerc, the phenomena to which Erasistratus refers take place somewhat as follows: "When the thorax or chest expands, the lungs also undergo dilatation and fill themselves with air. This air, entering first by way of the trachea, ultimately reaches the anastomosing terminals of the bronchial tubes, from which locality the heart, by the act of dilatation, draws it into itself, and then, immediately afterward contracting, sends it, by way of the great artery (the Aorta), to every part of the body." When it is considered that at this remote period of time nothing was known about oxygen and carbon dioxide, nor about the power of these elements to pass freely through a thin membrane (exosmosis and endosmosis), no surprise will be felt that Erasistratus carried the physiology of respiration no farther than he did. On the contrary, it is remarkable that he was able to describe so correctly this complicated process. In fact, none of his successors, up to the time when Harvey's great discovery was announced, was able to furnish a better description. The physiology of gastric digestion was another of the problems concerning which Erasistratus held views that were different from those commonly accepted by the physicians of that time. The stomach, he