SMUDGES AND FUMIGANTS. 39 



MERCURIC CHLORID. 



Surg. G. M. Guiteras," of the United States Public Health and 

 Marine-Hospital Service, has recounted a series of experiments with 

 mercuric chlorid, the use of which was first suggested to him by G. F. 

 Matzke, steward on the American steamer Beecham, who told Doctor 

 Guiteras that he had used it in the cabin of his vessel with success. 

 Doctor Guiteras carried out a series of five experiments in a room 

 12 feet high by 15 feet by ISJ feet, having a capacity of 2,385 cubic 

 feet, sublimating the mercuric chlorid in a porcelain evaporating 

 dish over an alcohol lamp. Mosquitoes in cages approximately con- 

 taining a cubic foot of space, covered with wire gauze, were exposed 

 at varying elevations in the room, and from 30 to 60 grams of mercuric 

 chlorid were sublimated at exposures varying from two to three hours, 

 at temperatures of from 77° to 88° F. Mosquitoes in the upper 

 part of the room were invariably killed, while some of those very 

 near the floor escaped, most of the latter, however, being killed, and 

 the remainder never recovering perfectly except in one experiment 

 where the temperature was only 77° F. Twenty-five grams of 

 mercuric chlorid were found to be sufficient for 1,000 cubic feet of 

 space. He showed that about twenty minutes are consumed in sub- 

 limating 60 grams of the chlorid; that brass work is not tarnished, 

 and that nickel-plated work and instruments are not tarnished when 

 wiped off immediately after fumigation. He further showed that 

 painted surfaces are unaffected unless the chlorid is sublimated close 

 to them and they are not immediately wiped off. Moreover, it does 

 not affect colored silk, cotton, or woolen goods. The poisonous quali- 

 ties of the substance, in Guiteras's opinion, do not constitute a real 

 danger. When the room was opened after the experiments, he 

 found it filled with a thick mist, but the room was entered without any 

 especial precaution and the windows were opened. In a few minutes 

 the vapor was carried away, leaving a slight deposit on the surfaces 

 within the room. This was allowed to remain for two or three days, 

 and the room was used in the meantime without any bad results. 

 The deposit, however, should have been removed with a damp cloth, 

 and with this ordinary care, the experimenter believes, there will be 

 no danger in the use of the substance. 



The advantages he considers to be the facility of obtaining mercuric 

 chlorid, the small quantity necessary, and the simplicity of its use; 

 a good alcohol lamp and a porcelain evaporating dish constitute all 

 the machinery necessary, and its use is certainly much more con- 

 venient than sulphur, where the operators have to carry about heavy 

 iron pots and barrels of sulphur. As to expense, he shows that at $1 

 per pound the 25 grams used per 1,000 feet cost somewhat less than 



a Public Health Reports, vol. 26, No. 50, pp. 1859-1861, December 10, 1909. 



