This treaty further provided that the United States should guarantee the independence of the Panamanian Republic, the terms being most explicit that the United States should protect the Panamanian Government from insurrection within and invasion from without. This little joker in the treaty between the United States and Panama makes that little republic the strongest of all the republics on the American continent next to our own. In fact, the Republic of Panama is as strong as the United States, and will be so as long as the American flag floats in sovereignty over a foot of American soil. The treaty also provided that the United States should have the privilege of sanitizing the cities of Panama and Colon, and that the cost of the same should be a charge against the Government of Panama. When all obstacles to the acquirement of the zone were removed under the Hay-Varilla treaty, the next step on the part of the American Republic was to begin the most important work of sanitization. Sanitization of the Canal Zone The sanitization of the Canal Zone and the cities of Colon and Panama is one of the most interesting features of the history of the Panama Canal. The want of proper sanitation was, no doubt, very largely the cause of the French failure. The French authorities, either not understanding the significance of maintaining the health of the great mass of employees engaged in their work, or being criminally negligent of the lives and the health of their employees, failed to take the necessary measures for the protection of life and health. Their laborers were allowed to live in a haphazard way. The negroes were permitted to furnish their own food and to sleep where they pleased. The consequence was that the ignorant and the improvident ate food that was not properly prepared, and slept very often in tents or on the ground, subject to the night dews and miasmatic vapors of the tropics. Diseases of the most virulent nature broke out in every camp, and yellow fever became especially active in carrying off its victims. [Illustration: THE EFFECT OF A BLAST ALONG THE CULEBRA CUT. Upper Picture--Before; Lower--After a Blast.] So with this dreadful experience as an example and a warning, the American authorities realized that the first work of importance was that of subduing the unhealthful conditions of the Canal Zone so that labor might be engaged in with reasonable safety by the tens of thousands of employees who would be placed upon the line of operations of the canal when work was actively commenced. Fortunately, surgeons of the American army had gained a great deal of experience during the Cuban campaign, and one army surgeon had achieved particular prominence in his handling of tropical diseases. Dr. W. C. Gorgas, who had campaigned in Cuba and assisted General Leonard Wood in the cleaning up and sanitization of Santiago and Havana, was peculiarly fitted for the important work of establishing healthful conditions on the Zone.