_Further Details Concerning the Advance in Our Knowledge of Gross Anatomy._--In the preceding chapter I have given some account of the efforts made during the sixteenth century by certain physicians to lay solidly the foundations of a gross anatomy of the human body. The time was ripe for such a movement, and the right sort of men took charge of it and pushed it forward to such a stage of successful accomplishment that we physicians of to-day are able to continue in the direction indicated, and under the impulse communicated, by these master builders. These men, it should be remembered, did something more than merely to lay solid and durable foundations in the form of an accurate anatomy, they also taught the correct methods of procedure for the erection of the superstructure of the science of medicine. Up to the end of the sixteenth century almost all the work done in anatomy was effected with the aid of the scalpel alone, the object being to isolate and expose clearly to view the larger tissues and organs, such as muscles, arteries, veins, nerves, etc. In a very few instances more elaborate methods were devised, even as early as during the fifteenth century, by men of exceptional cleverness. Thus, for example, in 1490, Alexander Benedetti, Professor of Anatomy at Padua, invented a method of preserving muscles, nerves and blood-vessels as permanent dry specimens, and it is said that he sold such preparations for large sums of money. As already stated on a previous page, the injection of blood-vessels with certain fluids was also employed to a very limited extent at this early period as a means of distinguishing them more easily from the surrounding structures; but this practice gave place, during the seventeenth century, to the better method of employing, as an injecting material, a semi-fluid preparation which became quite solid soon after it had penetrated well into the interior of the vessels, and to which any desired opaque color might be given. This method was invented by the Hollander, John Swammerdam (1627–1680) and perfected by Van Horne. It was largely by the employment of this procedure that Friedrich Ruysch of Amsterdam (1638–1731), Professor of Anatomy and Botany in the university of his native city, gained such celebrity throughout Europe for the great beauty of his permanent anatomical preparations. Hyrtl mentions the fact that Peter the Great of Russia, who resided for a certain length of time at Zaandam, near Amsterdam, in order that he might familiarize himself with the art of ship-building, was in the habit of visiting Ruysch from time to time in his museum and laboratory; and finally (in 1717) bought from him, for the sum of 30,000 florins, his entire collection of specimens, together with the formula of the mixture which he employed in making his injections. The collection itself, it should be stated, contained not only specimens illustrative of normal human anatomy (_e.g._,