Undoubtedly, the best anti-plague measures are those calculated to free the town from rats permanently, and these measures relate principally to rat-proofing the houses. In a general way, these measures consist in making a concrete floor, and in putting six or eight inches of concrete in the wall around this floor. With the whole town fixed up in this way, you would have no rats. At the same time, disposal of garbage should be carefully looked after, with the object of limiting the food supply of rats. Dr. Connor, of Colon, invented an excellent garbage stand, so arranged that a lid automatically closed the garbage can whenever the lid had been raised and released. If, however, a town has been made entirely rat-proof, that town is pretty secure from plague. If there are no rats there, no harm will be done, even if cases of plague come in, for there would be no means of transmitting it from man to man. If you have plenty of rats in a commercial city, such as Panama, in direct commercial relation with cities having plague, you are sure, in the course of time, to get in plague cases, no matter how good your quarantine, and if plague once gets in where there are plenty of rats it is very apt to spread. CHAPTER XXII THE WORK OF THE SANITARY DEPARTMENT OF PANAMA The work of the Sanitary Department of Panama has without question been a most useful adjunct in the construction of the Canal. It has enabled this work to be carried through with a minimum of loss, both in regard to sickness and death among employees engaged in construction work in the Canal Zone. We have no means of telling what was the sick rate with the French during the period of construction under the old French Company, from 1881 to 1889, but we know that it was very large. Our Army in Cuba during the Santiago campaign had during the last two months of our stay there a constant sick rate of over six hundred per thousand. Undoubtedly, the French rate approximated this during their period of active work, and we can safely calculate that their constant sick rate was at least three hundred and thirty-three per thousand, or one-third their force. Our force during the ten years of construction averaged thirty-nine thousand men. If we had had a similar constant sick rate, we should have had thirteen thousand sick employees in our hospitals every day during the ten years of construction. As it was, we had only twenty-three per thousand sick each day, a total of nine hundred for the whole force; that is, we had about twelve thousand fewer men sick every day than had the French. This twelve thousand men per day saved from sickness must be credited to the sanitary work done on the Isthmus.