An insecticide is an agent capable of destroying insect life. Many of the germicidal agents are also insecticides. There is a great difference in the resistance of different insects. Formaldehyde is a good germicide but is not an insecticide. There are four ways of using insecticides. In liquid form, powder, vapor form and those placed in food to be eaten by the insects.
Germicide
A germicide and a disinfectant are the same for they both destroy germ life. Many germicides are so powerful that they completely sterilize or destroy all life.
Deodorant
A deodorant is not in any sense a disinfectant and has no power to destroy germ life. It is an agent which neutralizes unpleasant odors. A disinfectant destroys germs but does not necessarily destroy odors. A deodorant must not be confused with a substance having pungent odor which merely substitutes one odor for another. A deodorant destroys the unpleasant odor.
Fumigation
Fumigation is a means of disinfection by use of fumes or gases, and is used generally for the purpose of destroying germ life only on the surface of objects. For this reason fumigation should not be used as a substitute for disinfection. Formaldehyde and sulphur dioxide are used largely for fumigating purposes.
Of these two gases formaldehyde is the better since it is not poisonous, does not injure the surface of objects and will not damage the most delicate fabrics nor destroy colors. Sulphur dioxide is very destructive and therefore less desirable. However, all the gaseous agents lack sufficient penetrative power to accomplish more than a surface disinfection. Formaldehyde is a good germicide and this adds to its efficiency.
To obtain the desired results in fumigating there must be special attention given the preparation of the rooms or spaces to be fumigated. All objects in the room should be so exposed that the gas may readily get to all surfaces. All furniture and other objects should be moved into the room away from the walls and all doors and drawers of bureaus and boxes should be opened so the gas may find free access to every nook and corner. Much of the gas may escape through cracks and crevices, therefore special care must be exercised that these openings are all properly closed before the fumigation is started. In view of the fact that the gas is non-destructive there is no harm done even to the most delicate materials.
The best results are obtained from the formaldehyde when the temperature of the room is 65° F. or over, with a relative humidity of at least 60%. While formaldehyde has the power to kill spores it is not considered sufficient to disinfect in such dis-eases as anthrax and tetanus.