252 Correspotidenre. \_A^\ 



Formalin is now easily obtained, is not expensive, and is neither 

 inflammable, nor has it any unpleasant smell. The vapor of formalin is 

 a powerful germicide, according to recent experiments ; and only a few 

 minutes are required for its complete dift'usion and the disinfection of a 

 room of moderate size. It is said to have no action on animal pigments. 



A recent article on ' The Disinfection of Books by means of the Vapor 

 of Formalin ' concludes as follows : 



" 1. Books can be disinfected in a closed space, simply by vapor of 

 commercial formalin by using i cc. of formalin to 300 cc. or less of air. 



2. The vapor of formalin is rapid in its disinfectant action. The effect 

 produced in the first fifteen minutes is practically equivalent to that 

 observed after twentj'-four hours. 



3. An increase in the amount of air to each cc. of formalin is not 

 counterbalanced by an increase in the length of time of exposure. 



4. In case the disinfection has been incomplete, the vitality of the 

 organisms has been so weakened that they survive only if transferred in a 

 few hours to media suitable for their development. 



5. The use of vapor of formalin is not detriinental as far as observed 

 in any manner to the books, nor is it objectionable to the operator beyond 

 a temporary irritation of the nose and eyes, somewhat similiar to that 

 produced by ammonia." 



Having no infested bird-skins, and being unable to find any Dermesles, 

 or other beetles, I can only speak of its effect on the ' Clothes Moth ' and 

 larvce. A number of the moths and caterpillars with the material on 

 which they were feeding, were put in the trays of a museum case, 

 about 5i cu. ft. in capacity; and in the middle tray a saucer holding a 

 couple of teaspoonfuls of commercial formalin. The can was kept shut 

 for an interval varying from two hours to five minutes, the experiment 

 being repeated a number of times. Exposure to the vapor for half an 

 hour or more was fatal to both moths and larva;; while often fifteen 

 minutes in the case was enough to kill the inoth, and less frequently the 

 caterpillers as well. A longer time may be needed for the formalin vapor 

 to reach and destroy insects which are not on the outside of the speci- 

 mens, and possibly the disinfection may be found not to be only superfi- 

 cial at best. 



If the alcholic solution — ' holzine ' — can be obtained it would doubt- 

 less be better than ' formaline,' which is the aqueous solution of formic 

 aldehyde. 



I hope others will try this disinfectant, and report its success; for it 

 would certainly be a gain if it were necessary to ' quarantine ' our collec- 

 tions for only an hour or two, and without the odor and risk of fire, 

 which now accompany the process. 



Respectfully yours, 



Arthur P. Chadbourne, 



225 Marlborough St., Boston, Mass. 



