190 MOSQUITOES 



by this application, if only it is drawn from below and not 

 dipped out. 



For pools or puddles of a somewhat permanent character, 

 draining or filling-up is the best remedy. 



The medical department will furnish oil for the purpose above 

 mentioned. 



Post commanders will carefully carry out these precautions. 

 By conniiand of Major-General Wood : 

 H. L. Scott, 



A dju taut- General. 



Dr. Keed informs me that this order was drawn up by 

 Colonel J. E. Kean, United States Army, Acting- Chief 

 Surgeon of the Division of Cuba. Colonel Kean wrote, 

 under date of January 12th, that he made the interval 

 between the applications of kerosene twice a month in- 

 stead of once a month, as he had been unable to find in 

 Cuba an oil of sufficient diffusive quality over the surface 

 of the water, which at the same time would be less vola- 

 tile than the common illuminating kerosene. The lubri- 

 cating oils experimented with did not spread readily. 



Mr. Kerr's Staten Island exi^erience w^as an extensive 

 one and led to interesting results. He writes me : 



While I do not know how long the protection was afforded 

 by each treatment of the pond-surface, my judgment was that it 

 covered a period of at least several weeks. I think much depends 

 upon the surrounding natural conditions. An exposed pond 

 reasonably clear of weeds and grass and Avith a fairly clean shore- 

 line, liberally treated with a non-volatile fuel oil, is quickly 

 covered with an oily scum, which the first wind blows over to one 

 side. Then with a change of wind it is blown hither and thither, 



